Sweet Escapade: Boston Cream Pie

Boston Cream Pie is a classic cake (yes not a pie) made with a sponge cake base filled with rich vanilla custard and a chocolate ganache coating on top. This is a classic flavour combination for a reason. The butter cake is light and fluffy and pairs perfectly with the creamy custard and rich chocolate glaze, If you love classic custard and chocolate together then please give this a try.

Boston Cream pie was said to have been invented by Armenian-French chef Mossburg Sanzian in 1856. It made made its debut at the grand opening of Boston's Parker House, which is now Omni Parker House, located in downtown Boston, MA. The chef was said to have been lured by a $5,000 annual salary which at the time was more than 10 times the average pay for similar positions at the time.

Whether the Boston Cream pie was his own invention or a riff on the Washington Pie, an already known dessert at the time is not known. However the Washington Pie did not have the chocolate topping. As Boston was the site of the first chocolate mill in the United States chocolate was readily available treat there while not in other areas of the country yet. Walter Baker & Company was the United States' first chocolate factory located in Dorchester, Boston. Similar to the cake, a Boston Cream Donut is filled with custard with a chocolate top.

Why is a Boston Cream Pie called a pie and not a cake? It's clearly a cake. Apparently it came from a time when cakes were baked in the same pans. Other similar names were cream pie or custard cake.

There are three parts to a Boston Cream Pie: the cake, the custard and the chocolate ganache.

The Cake: This is a butter sponge, the same one that I use in this strawberry cake because of its versatility, classic flavour and lightness. My secret ingredient for this is the zest of 1 lemon. It really lifts the sponge flavour so much.

The Custard: This can be the trickiest part. You want the custard to be silky but also hold its shape. Adding cornflour helps it keep its shape but you don't want to add too much as it will detrimentally affect the mouthfeel. The best thing to having the custard set is time and using full fat thickened cream. Also make sure to chill it in the fridge for the times specified. Cutting these times may mean that your custard won't set completely (believe me I was impatient and it messed the whole thing up!).

The Chocolate Topping: The chocolate ganache is the easiest part. Just heat cream, add the dark/bittersweet chocolate and corn syrup or glucose syrup (for shine) and then pour over. Et viola! Your Boston Cream Pie is ready.

I made this cake so many times, three to be exact but I wanted it to be just right. It's not a small cake and it's involves using lots of eggs, milk, cream and chocolate. The first one was made in a bit of a hurry and while the sponge was perfect, the custard had not set properly as I didn't leave it the requisite time.

The second time I was too busy chatting to my cleaner Fernanda while making the sponge and I accidentally placed the sugar in with the hot milk and it didn't rise properly and didn't have the right crumb to it!

The third time is a charm or so they say and I made it and it worked perfectly. I was so happy with it that I cut it up and shared it with my neighbours and left two big slices in the fridge for Yuki who was house sitting for us while we were away. We were so lucky to have found her, she was great with the dogs and a very gentle person so we knew that the dogs were in good hands. That morning she arrived and made herself at home. She had some clothes with her and I was running around packing the last items. "I always forget one thing," said Yuki smiling and I said that I was the same but that I thought that I had everything.

She waved us goodbye with Teddy and Milo and we drove off into the heavy traffic towards the South Coast. We were about 20 minutes into our drive when I said with a start, "Did you leave her keys?" to Mr NQN. "Bugger no," he said grimacing. We tried calling Yuki and giving her instructions on how to find the spare set of keys but she wasn't able to find them. So we turned around and made our way back. By the time we dropped the keys off we were running 50 minutes late. And that thing that you always forget? Well it might not be leaving your keys behind!

So tell me Dear Reader, have you ever tried Boston Cream Pie? Do you always leave something behind?

Boston Cream Pie

An Original Recipe by Lorraine Elliott

Preparation time: 30 minutes plus 2.5 hours cooling time

Cooking time: 35 minutes

Vanilla Sponge Cake

• 1 1/4 cups/310ml/11flozs. whole milk
• 1 stick/113g butter
• 1 teaspoon salt
• 1 3/4 cups/385g/13.6ozs caster or superfine sugar
• 4 large eggs, room temperature
• 2 teaspoons vanilla bean paste
• Finely grated zest of 1 small lemon
• 2 cups/300g/10.6ozs cake flour*
• 2 teaspoons baking powder

For Custard Filling

• 100g/3.6ozs egg yolks (around 6)
• 115g/4ozs caster or superfine sugar
• 35g/1.2ozs cornflour/fine cornstarch
• 250ml/8.8flozs cream
• 250ml/8.8flozs full cream milk
• 20g/0.7oz butter
• 1 tablespoon rum
• 2 teaspoons vanilla bean paste

For Cake

• 2 tablespoons sugar syrup
• 1 tablespoon rum (sub with more syrup if you don't want to use alcohol)
• 100g/3.5ozs dark chocolate chip
• 100g/.5flozs cream
• 2 tablespoons glucose or corn syrup

Cake flour can be bought at the supermarket. You can also make it at home. To make 1 cup/150g/5.2ozs of cake flour replace 2 tablespoons of plain all purpose flour with cornflour/fine cornstarch and whisk well. I usually mix up a big batch of this and keep it in a container ready for baking cakes as it produces a softer texture.

Pro-tip: place your mixing bowl and whisk or Thermomix bowl in the fridge 1 hour before whipping the cream and make sure that the cream is very cold. This will help the cream whip up better.

Step 1 - Make the custard first as it needs to chill for 2 hours. Whisk the egg yolks, sugar and cornflour together and heat the cream and milk in a medium saucepan until almost boiling. Take off the heat and stir in the egg mixture, butter, rum and vanilla and cook on low to medium heat making sure that it doesn't catch at the bottom (just stir it occasionally). Cook it until the texture can coat the back of a spoon (it will thicken further upon cooling). Place in a bowl and cover the top directly with cling film and chill for 2 hours in the fridge.

Step 1b Thermomix - Place the egg yolks, sugar, cornflour, cream, milk, butter, rum and vanilla in the TM bowl and set to 6 minutes, 90C speed #4. Place in a bowl and cover the top directly with cling film and chill for 2 hours in the fridge.

Troubleshooting: if your custard splits add in a couple of cubes of ice and stir rapidly.

Step 2a - Line a 40x30x5cm/15.7x11.1x2inch Swiss roll tin on the base and sides with parchment. Preheat oven to 160C/320F. In a saucepan heat the milk and butter until the butter has melted and stir in the salt (do not boil, just scald the milk). Set aside in a jug. Sift the flour, baking powder and salt together into a bowl. In the bowl of a mixer fitted with a whisk attachment whisk the sugar, eggs, vanilla and lemon zest for 5 minutes until syrupy thick and very pale yellow (almost white). Add the hot milk butter mixture and whisk for 15 seconds or until incorporated. Then sift in the flour mixture and whisk on low speed in two lots until smooth (do not overmix). It will be a very liquidy batter.

Step 2 b Thermomix directions - Line a 40x30x5cm/15.7x11.1x2inch Swiss roll tin on the base and sides with parchment. Preheat oven to 160C/320F. Add the milk, butter and salt into the Thermomix bowl and set to 3 minutes, 100C, speed #1. Pour into a jug and set aside. Add the sugar into the bowl first (so that the residual bowl heat doesn't cook the eggs) and then the eggs, vanilla and lemon zest and insert butterfly whisk. Set to 3 minutes, speed #4 -it should be very pale yellow (almost white) and syrupy in texture (see above). Add the hot milk butter mixture and set to 15 seconds, speed #4. Then sift in the flour, baking powder and salt and set to 10 seconds, speed #4. It will be quite a very liquidy batter.

Step 3 - Pour into the prepared tins and bake for 20-23 minutes or until the centre springs back when gently pressed. Cool on a cake rack. Cut out 2x20cm/8inch rounds of cake.

Step 4 - Place one half of the cake onto a cake stand. Mix the syrup with the rum and brush half onto the base. Whisk the custard until it becomes smooth. Spread over the cake half leaving 1/2 a cup or so. Place in the fridge for 30 minutes. Then take the other cake and brush with the rest of the syrup on and place on top using domed side up. Use the extra custard to fill in the top gap piping it in. Refrigerate for 2 hours. Scrape the sides with a dough scraper or angled spatula so that the custard sits smoothly on the side.

Step 5 -Make the ganache - place the chocolate in a medium sized heatproof bowl. Heat the cream until almost boiling and then pour over the chocolate. Place a plate on top and leave for 5 minutes. Then stir until smooth and there are no lumps left. Cool for 10-15 minutes. Then pour in the centre of the top of the cake and using an angled spatula, spread out allowing some to drip down the sides.

Storing and serving: store the cake in the fridge in an airtight box. When serving, bring it out of the fridge 30 minutes before serving.