1. Place milk, half of the sugar, and salt into a saucepan and heat over medium heat until simmering.
2. Combine the second half of the sugar with cornstarch in a mixing bowl. Add the egg yolks and vanilla. Whisk until a homogenous consistency is reached without lumps.
3. Add approximately ½ of the hot milk to the egg yolk mixture while whisking vigorously to temper the eggs. Then, pour the egg mixture back into a saucepan with the rest of the hot milk.
4. Return to the heat. Cook over low heat for 5-7 minutes, whisking consistently until the mixture becomes pudding-like in consistency (this is so-called pastry cream or custard cream), then cook for 2 minutes. If lumps appear, whisk vigorously and they will dissolve.
5. Remove from the heat and pour the mixture into a large, shallow dish. Cover the pastry cream with plastic wrap so they touch each other, then leave it to cool down to room temperature.
6. In a stand mixer fitted with a whisk attachment (or use a hand mixer and a large mixing bowl), beat the butter with 15g of sugar until white and fluffy.
7. Whisk the pastry cream with a whisk until smooth again.
8. Add the pastry cream a couple of tablespoons at a time to the butter and whisk every time on medium until incorporated. Continue until all pastry cream is combined with the butter. Scrape the sides and the bottom of the bowl, then beat again for 10 seconds. Here you have your mousseline cream for Carpathian cream cake.
9. Assemble your Karpatka cake and chill. Then, dust with powdered sugar and serve.
FAQ
How long does Karpatka cake last in the fridge?
It will last for up to 3 days. Also, you can make the choux pastry in advance and keep it in the fridge for 2-3 days, then bake.
Can you freeze Karpatka cake?
You can freeze baked cake layers for up to 1 month but you can’t freeze the cream. It’s also not recommended to freeze unbaked choux pastry.
