Step 1

1)Add the milk and espresso powder to a saucepan; bring the mixture to a simmer, almost to a boil. Whisk to dissolve the coffee powder.

Step 2

2)While the milk is heating, whisk together the egg yolks and sugar in a bowl until they are well combined, smooth, and a lighter color.

Step 3

3)Add the cornstarch and flour to the egg mixture. Whisk until smooth.

Step 4

4)When the milk begins to simmer, and small bubbles appear, remove it from the heat. Then, gradually pour the hot milk over the egg yolk mixture while whisking constantly.

Step 5

5)Bring the mixture back to the saucepan and cook over medium heat, stirring constantly, until it begins to thicken.Let the cream come to a boil, then lower the heat and cook for 1 to 2 minutes longer. Once cooled, the cream will be thicker.

Step 6

6)Remove the cream from the heat and pour it into a glass or ceramic bowl. Add the butter and let it melt for 2 to 3 minutes.

Step 7

7)Whisk the butter until completely melted and mixed in. At first, the coffee pastry cream will look curdled; keep whisking until smooth.

Step 8

8)Cover it with plastic wrap pressed directly onto the surface of the cream to prevent skin from forming on the surface of the pastry cream while it chills.

Step 9

9)Place in the fridge as soon as possible and let it cool completely for 2 hours at least or overnight. When ready to use the pastry cream, stir it with a spatula to loosen it.