Boston Cream Pie Karpatka

Choux Pastry
2 Preheat the oven to 425 F and place a rack in the middle of the oven.
3 Measure out the flour in a small bowl and set aside.
4 In a medium sauce pot, add in the butter, water and salt.
5 Heat over medium heat until just simmering. Briefly stir so that the water and butter are combined.
6 Turn the heat to low and immediately dump all of the flour in at once.
7 Use a wooden spoon to stir the dough together for about a 60 seconds. Once the dough starts to form a smooth ball, start stirring and mashing it more forcefully.
8 Once cooked, place the dough into the bowl of a stand mixer and set it aside.
9 Crack the eggs into a bowl or cup, ideally one with a spout for easier pouring and scramble with a fork until smooth.
10 Use the paddle attachment on the mixer to beat the cooked dough for 3-4 minutes on medium low speed. This will help cool the dough before adding the eggs in.
11 Leave the mixer running and gently pour 1/3 of the egg mixture in.
12 Increase the speed of the mixer to medium and mix until the egg has been fully combined into the dough.
13 Stop the mixer and scrape down the sides of the bowl. Then repeat the process of adding egg and mixing but you may not use all of the egg! The best way to know is to stop mixing and pull the paddle out of the batter slowly -it will stretch briefly and then break off in a V-shape. If it breaks immediately and makes a jagged edge, you need more egg.
Bake the Choux
15 Line two 8" metal round cake pans with parchment and then divide the dough evenly between the two.
16 Use an offset spatula, dipping it in water as needed to prevent sticking, to spread the dough into even layers in each cake pan.
17 Bake the choux in the hot oven for 20 minutes, then with the oven CLOSED, turn the heat down to 400 F and bake for another 15 minutes.
18 Once golden brown and puffy, take the pans out of the oven and leave them and the choux to cool completely.
Make the pastry cream
20 In a large pot, whisk together the corn starch and sugar. *If you need to do this in two batches you can! Then pour in the milk and 150 grams of the heavy cream and whisk to combine. Add in the egg yolks and salt and whisk once more.
21 Place the pot over medium low heat and whisk constantly scraping the bottom and edges of the pot. It will feel like it’s taking a while but all of a sudden it’ll get really thick so don’t stop whisking. *It will get really thick, don’t stress.
22 Once thick, remove the pot from the heat and whisk in the butter and vanilla bean paste until smooth.
23 Pour the cream through a fine mesh sieve into a large shallow bowl or on a quarter sized baking sheet. Cover the surface with a layer of plastic wrap to prevent a skin from forming.
24 Once cooled to room temperature, transfer the cream to the fridge and let it chill completely – this one needs to be fridge cold!
Pecan Pie Filling
26 In a small pot add in the brown sugar, maple syrup, butter, milk, and salt. Heat over medium low heat until melted, stir and cook until combined and just bubbling.
27 Turn off the heat and pour in the vanilla.
28 Finely chop up the pecans - we're not going for flour but they shouldn't be huge chunks. Ideally 1/4" or smaller.
29 Add the chopped pecans into the pot and stir to combine. Transfer the mixture to a small bowl and place it in the fridge to cool and thicken.
30 This doesn't need to be cold before using just somewhat syrupy and thick and should no longer be hot.
Assemble
32 Transfer the chilled pastry cream to a large mixing bowl and use an electric mixer to whip until smooth.
33 Then add in the remaining 150 grams of cold heavy cream and whip until smooth and fluffy.
34 You can either assemble this in an 8" springform pan or with this metal cake collar. I did it with the metal cake collar on a large flat plate.
35 Place one layer of the choux, flat side down, onto a large flat plate or small tray that will fit in the fridge. Tighten the cake collar around the choux.
36 Scoop half of the pastry cream over the base layer of choux and spread it into an even layer. Spoon the cooled pecan pie filling over the pastry cream into an even layer all the way to the edges.
37 Scoop the remaining half of the pastry cream over the filling and again smooth it into an even layer.
38 Place the second layer of choux, again with the flat side down, onto the pastry cream and press down to squeeze out any air.
39 Drape a piece of plastic over the top and set it in the fridge for 6 hours or overnight to set.
Chocolate Ganache
41 Add the chopped chocolate into a medium heat safe bowl. Heat the heavy cream in a pot or the microwave until just steaming hot, not boiling.
42 Pour the hot cream over the chocolate, cover with a lid and let it sit for 1 minute. After a minute has passed, remove the lid and whisk slowly until smooth.
43 Take the chilled and set cake out of the fridge. Remove the plastic wrap and release and remove the cake collar. Transfer the cake to whichever dish you plan to serve it from.
44 Pour the chocolate ganache all over the top of the cake. I like to let it run down the edges as well but it's up to you! If needed use the back of a spoon to spread it out over the surface.
45 Place the cake back in the fridge for 10 minutes to let the ganache firm up just a little - we don't want it to be hard just not so runny.
46 To serve, use a long serrated knife parallel to the top of the cake just to cut through the first layer of choux. Then switch to a big straight knife to cut through the cream and bottom layer. Store leftovers in the fridge for a day or two.