Sift together the all-purpose flour, cocoa powder, baking powder, and salt. Set aside.

Chop or grate the bittersweet chocolate into very small pieces.

Place the unsalted butter, firmly packed sugar, spices, freshly grated lemon, and orange zest in a mixer and beat on medium-high speed until creamy (about 3 minutes).

Scrape down the sides of the bowl with a rubber spatula. Beat in the pure vanilla extract.

Add the eggs one after the other, making sure each is incorporated fully into the batter before adding the next.

Scrape down the sides of the bowl with a rubber spatula.

Mix again to make sure everything is evenly combined.

Turn the mixer speed down to low. Add half the sifted dry ingredients.

Add the wine and then the rest of the dry ingredients.

Mix in the chocolate.

Preheat the oven to 400F.

Grease an 8 x 12 pan and line with baking paper.

Spread the batter out evenly into the pan.

Bake for 25 minutes or until a knife inserted into the center of the cake comes out clean.

Transfer the cake to a cooling rack set up over a parchment paper-lined baking sheet. Let cool completely.

Whisk together the powdered sugar and red wine until it forms a smooth glaze.

Pour the glaze onto the cake and use a rubber spatula to even it out over the top.

When the glaze has dried, cut the cake into small pieces. Arrange on a platter and serve.