Cake:
1/3 cup cocoa powder, plus more for dusting pan (not Dutch process)
2/3 cup water
1 cup sugar
3 ounces of good-quality bittersweet Chocolate (70% cacao)
2 eggs
1 and ¼ cups all-purpose flour
6 tablespoons butter
2 teaspoons baking powder
1/3 cup neutral vegetable oil
½ teaspoon salt
1/3 cup buttermilk
Preheat oven to 300 degrees.
Butter a deep 9-inch round cake pan and line the bottom with parchment paper. Butter the paper and dust it with cocoa powder.
Melt chocolate with the cocoa, butter, oil, and water over low heat (or double boiler), stirring until smooth. Remove from heat and whisk in sugar.
Cool completely, then whisk in the eggs one at a time.
Combine the flour, baking powder, and salt. Whisk into the chocolate mixture. Shake the buttermilk well, measure, and stir into the batter.
Pour the batter into the ban and bake on the middle oven rack for about 45 minutes or until a toothpick comes out clean.
Cool on a rack for 10 minutes, turn out, remove parchment, and cool completely.
Frosting:
Mix two tablespoons of sugar into one cup of mascarpone. Spread frosting on the top of the cake. Add Praline or fruit on top.
Pralines:
1/2 cup of slivered blanched almonds
1/4 cup water
1/2 cup blanched hazelnuts
3/4 cup sugar
Toast nuts in a 350-degree oven for 10 minutes.
Combine water and sugar and boil, stirring until the sugar dissolves. Boil without stirring until it darkens, swirling the pan until the mixture turns to deep gold. Remove from heat and stir in the nuts.
Carefully turn out onto a baking sheet lined with parchment or silpat, spread evenly with a spoon, and cool completely. Be careful; sugar burns hurt.
Once cool, break into pieces, put them in a plastic bag, and smash until you have small pieces to sprinkle over the frosting for crunch and flavor.
Variations:
Praline is a hassle; fresh berries (raspberries work well) can be substituted as a topping or crushed peppermint candies etc.
A single-layer cake can be split, with the middle frosted (it will need more frosting) and filled with the fruit of your choice.
It also works well if feeding a crowd as a two-layer cake (double the cake recipe) with the middle frosted and filled with fruit or praline, etc., and cut into slabs, as your grandmother taught us.