Vanilla Custard Cream Squares

A vanilla custard square on a white plate. The rest of them are in a baking pan in the background.

These vanilla custard cream squares are a traditional Polish dessert, also called Karpatka. Two layers of choux pastry sandwich a delicious vanilla custard filling, and the tops are dusted with powdered sugar for a finishing touch.

Course Dessert

Cuisine polish

Prep Time 30

Cook Time 30

Chilling Time 1

Servings servings

Calories 370kcal

Author Nina

Ingredients

Choux Pastry Layers

1 cup water
½ cup unsalted butter
1 cup all purpose flour
5 large eggs room temperature

Vanilla Custard Filling

3 cups milk divided
¾ cup granulated sugar
¼ cup unsalted butter
5 large eggs room temperature
1 teaspoon vanilla extract
7 tablespoons cornstarch
¼ cup powdered sugar for dusting finished squares

US Customary - Metric

Instructions

Choux Pastry Layer

Preheat oven to 400°F (200°C). Line 2 baking trays with parchment paper. Set aside.
Add water and butter to a medium saucepan over medium heat. Bring to a boil, then add flour. Stir with a wooden spoon continuously until the dough comes together, and a thin starchy film forms on the bottom of the pan, about 2 minutes.
Remove from heat and transfer dough to a stand mixer fitted with the paddle accessory, and mix until the dough cools down a bit, about 2 minutes.
Add eggs one at a time, making sure each one is incorporated into the dough before adding the next.
Give the dough a good final mix. Divide the dough in two and place each half on the prepared baking sheets. Spread out the dough with an offset spatula to make a rectangle. It doesn't have to be perfect, but try to make each on roughly the same size.
Bake the layers for 25-30 minutes, then remove from oven to cool completely on their baking trays.

Vanilla Custard Filling

Whisk eggs, vanilla, and cornstarch together. Whisk in 1 cup of milk and set aside.
In a medium saucepan, bring remaining 2 cups of milk, sugar, and butter to a boil. Add in egg mixture and whisk continuously for 2-3 minutes until mixture begins to boil and thicken. Remove from heat.
Pour the hot custard mixture onto one sheet of choux pastry. Use an offset spatula to spread it over the pastry, leaving a 1-inch border.
Top with the other sheet of choux pastry and lightly press down so it sticks to the custard.
Refrigerate until custard has cooled and set, about 1 hour. Dust with powdered sugar and cut into squares.
Leftovers will keep in the refrigerator for up to 3 days.

Notes

I like using full fat milk in baking recipes. You can substitute 2% milk. I don't recommend any lighter fat milk than that.

While making the choux pastry, make sure you add in one egg at a time and wait for it to get fully mixed in before adding the next. Give it a good long mix after all the eggs have been mixed in to make sure it's done.

If your custard is lumpy, whisk it with an electric mixer. After a minute or so, it'll be smooth again!

The custard needs to firm up to hold it's shape. Don't skimp on the chilling time.

Nutrition