Use a fork to poke holes all over the pie crusts and bake in a 220°C - 180°C oven for 25 minutes. After 6 - 7 minutes, use a spatula to deflate the puffiness.
Dust the entire crust with powdered sugar sprinkled through a tea strainer, and bake again for 3 - 4 minutes at 230°C.
Once the entire surface has become a glossy caramel color, it's done.
Put the granulated sugar from A into a pot and heat on medium.
When it turns a thick, dark caramel color, stop the heat and add the heavy cream.from A. Stir together.
This is what it looks like after the cream has been added.
Add the milk and bring to a boil. It's okay if the caramel begins to stick to the bottom of the pot because it will gradually dissolve.
In a bowl, mix together the egg yolk, granulated sugar, and sifted flour + cornstarch mixture, in that order.
Add Step 7 into Step 8 and blend together. Pour it back into the pot and turn on the heat to medium-high. While using a whisk to stir, heat until the center comes to a boil and it is completely heated through.
Pour it into a metal tray, cover with plastic wrap, top with an ice pack and cool quickly. This completes the caramel custard.
Mix together all of the B. ingredients in a bowl. Place the bowl in a bowl of ice water and lightly whip until fluffy peaks are formed.
Strain Step 10 and stir in the rum. Add 40g of Step 11 to Step 10 and fold it in with a rubber spatula.
Cut the pie crust into 6 sections. Using a serrated knife, first cut just the caramel's surface, then vigorously push the knife down to cut through the rest.
Use a piping bag with a star-shaped tip to pipe cream from Step 12 onto the 6 pie crust strips.
Top with 5mm thick roundly sliced bananas. It's difficult to move them after this, so you should put them on a serving dish.
Pipe the rest of the heavy cream in a straight line.
Top with the remaining 6 pie crusts and it's all done!
Story Behind this Recipe
This mille-feuille has an extraordinary balance between the caramel and the banana. Using an IH induction cooker helps the caramel to cook smooth and even, and also keeps from getting too hot while simmering. It's very convenient.
Before baking the pie crust, make sure you use a fork to poke some holes for ventilation. After you break up the puffing once, if it begins to expand again, break it once more. I used Heavy Cream, I used a 36-37% low-fat dairy cream.