Preheat the oven to 350º F.

Spray a baking sheet with non-stick cooking spray, line with parchment and spray the parchment.

In a small bowl, sift together the flour, cocoa powder, cornstarch and baking soda and set aside.

In a large metal bowl set over barely simmering water, whisk eggs and sugar with a balloon whisk until thick, foamy. Transfer the bowl to a standing mixer and continue to whisk until the mixture has tripled in volume and ribbons form when the whisk is lifted, about 10 minutes.

At this point, the roulade is ready to be filled, iced and decorated (if you are making a roulade or a Buche de Noel).

Remove from the heat and gently fold in the flour mixture until just combined. Fold in the melted butter and pour into the prepared baking sheet.

Bake for 15 minutes or until the cake is springy to touch. Cool in pan for 3 minutes, then run a knife along the edges. Turn cake out onto a wire rack draped with a kitchen towel and carefully peel away the parchment. The towel should be on the underneath side of the cake. Sprinkle the cake with the chocolate liquor.

To roll the cake, start at one of the long sides, gently roll the cake inside the towel. Let the cake cool, seam side down for 30 to 35 minutes.

This cake can also be baked in an 8-inch round pan. Bake for 20 minutes until the cake is springy to the touch. Cool in the pan on a wire rack for at least 10 minutes before turning out onto the rack to cool completely.