Chocolate roll with butter cream

I propose to cook a biscuit chocolate roll with butter cream - wonderful, airy!

Ingredients

• For test:
• Egg whites - 8 pcs.
• Sugar - 180 g
• Chocolate black - 100 g
• Flour - 60 g
• For cream (you can use half of the indicated amount of products):
• Sugar - 100 g
• Starch - 30 g
• Egg yolks - 2 pcs.
• Milk - 375 ml
• Butter (room temperature) - 250 g
• Vanilla sugar - 5 g
• Besides:
• Strawberry jam - 2 tbsp. l.
• Cocoa powder - 1 tsp
• Powdered sugar - 2 tsp

Directions

1. Melt the chocolate in a water bath. While we are preparing the cream, it will cool down.
2. Mix half the sugar and cornstarch in a bowl. Add vanilla sugar, mix. Add egg yolks and a couple of tablespoons of milk, mix. Pour in half the milk and mix well.
3. Pour the remaining milk into a saucepan and add the remaining sugar. Bring to a boil, stirring constantly, over low heat.
4. Pour the mixture with diluted starch in a thin stream, stirring all the time, cook until thickened.
5. Remove the cream from the stove, cover with cling film so that the film touches the cream. The cream must be completely cold.
6. While the cream is cooling, we proceed to the preparation of the biscuit. Beat egg whites in a clean, dry bowl with a clean, dry whisk until stiff peaks form.
7. Continuing to beat, gradually add sugar, beat until the sugar is completely dissolved.
8. Add cooled melted chocolate. Pour the flour, mix everything gently with a silicone spatula so that there are no lumps left. The mass will fall by half, do not be alarmed.
9. Put the mass into a culinary bag with a large round nozzle, put strips of dough on parchment. (It's easier to put the dough on a baking sheet covered with parchment and smooth the surface.)
10. Bake a biscuit in an oven preheated to 220 degrees for 10-12 minutes.
11. Take the biscuit cake out of the oven and leave it on the baking sheet for 10 minutes.
12. We cover with parchment on top, turn over, remove the parchment on which the cake was baked, cover with clean parchment and roll it up with paper. Let cool completely.
13. We turn back to the preparation of the cream. Beat the softened butter until fluffy, gradually add the cooled custard (the custard should be the same temperature as the butter), beat until fluffy.
14. We unfold the biscuit, remove the paper. Lubricate with jam. Apply a layer of cream.
15. Roll up and place in the refrigerator overnight.
16. Sprinkle chocolate roll with cocoa powder and powdered sugar.
17. Cut the chocolate roll with cream into pieces and serve with a cup of hot tea or coffee.