Chocolate mini rolls

Ingredients:

Sponge cake

• 1/4 tsp cream of tartar
• 6 large eggs at room temperature, separated into yolks and whites
• 3/4 cup sugar
• 1/4 cup milk
• 1/4 cup vegetable oil
• 1 tsp vanilla extract
• 3/4 cup premium flour
• 1/4 cup cocoa powder + extra for sprinkling
• 0.5 tsp baking powder
• 1/4 teaspoon fine salt
• Special equipment: baking tray measuring 45×32 cm.

Filling

• 1 cup heavy cream
• 1/3 cup light corn syrup
• 0.5 tsp vanilla extract

Glaze

• 220 g semi-sweet chocolate, chopped
• 0.5 cups heavy cream
• 1 tbsp. unrefined coconut oil
• 1/4 tsp vanilla extract

Preparation:

1. Preheat oven to 375°F (190°C). Spray a 18 x 13-inch baking pan with cooking spray; line the bottom with parchment paper and spray the parchment.
2. Sponge cake:
   
   In a medium bowl, beat the egg whites and cream of tartar with a mixer on medium speed until soft peaks form, about 3 minutes. Gradually beat in 1/4 cup sugar. Increase the speed to medium-high and beat until stiff peaks form, 3-4 minutes.
3. In a large bowl, combine the egg yolks with the milk, vegetable oil, vanilla extract, and the remaining 1/2 cup sugar. Sift the flour, cocoa powder, baking powder, and salt into a medium bowl; stir into the yolk mixture until smooth. Fold one-third of the beaten egg whites into the batter with a spatula, then gently fold in the remaining egg whites in two batches.
4. Place the dough on the prepared baking sheet. Bake until the cake springs back when gently pressed, about 10 minutes. Let cool for 5 minutes.
5. Generously sift cocoa powder over the warm sponge cake and loosen the edges with a knife. Place a clean kitchen towel (not terrycloth) on top of the cake. Place another baking sheet on top of the towel and invert the cake so that it is on the towel. Remove the top baking sheet and parchment, then dust the cake with cocoa powder. Roll the cake up along the long edge, using the towel as a base. Transfer the cake, seam-side down, to a wire rack and let cool completely.
6. Filling:
   
   Combine the cream, corn syrup, and vanilla extract in a medium bowl and beat with a mixer until stiff peaks form. Refrigerate until ready to use.
7. Glaze:
   
   Heat the chocolate, cream, coconut oil, and vanilla extract, if using, over a double boiler, stirring occasionally, until the chocolate is melted and the mixture is smooth and warm, about 4 minutes. Let cool slightly.
8. Unroll the roll and spread the filling onto it. With one short side facing you, cut the sponge horizontally into 6 strips, then cut in half vertically to create 12 strips measuring 7.5 x 16 cm. Roll the strips up to form tight mini-rolls. Shake off any excess cocoa powder. Refrigerate for 15 minutes.
9. Place a wire rack on a baking sheet. Arrange the rolls on the rack, making sure they aren't touching, and pour the glaze over them, completely coating them on all sides. Refrigerate for at least 15 minutes to allow the glaze to set before serving.