Preheat the oven to 350°. Butter and flour a 12-cup bundt pan. In a bowl, whisk the flour, cocoa powder, baking soda and salt.
In a large bowl, using a handheld electric mixer, beat the butter with the sugar at medium-high speed until fluffy, 4 minutes. Add the eggs, one at a time, and beat until incorporated. Add the vanilla and beat for 2 minutes longer. Working in two batches, alternately fold in the dry ingredients and the wine, until just incorporated.
Scrape the batter into the prepared pan, and bake for 45 minutes, until a toothpick inserted in the center comes out clean. Let the cake cool in the pan for 10 minutes, then turn it out onto a rack; let cool completely. Dust the cake with confectioner's sugar and serve with whipped cream.