2 cups sugar
4 ounces unsweetened chocolate
1/4 pound unsalted butter (1 stick), plus more for greasing the pan
2 cups all-purpose flour, plus more for dusting the pan
2 teaspoons baking soda
1 teaspoon baking powder
1 teaspoon semi-coarse sea salt or kosher salt
1 cup milk
1 teaspoon cider vinegar
1 teaspoon vanilla extract
1 1/2 cups Nestle semi-sweet chocolate chips
1 1/2 cups sour cream, at room temperature
Preheat the oven to 375 degrees, and place a baking sheet on the lowest rack, to catch any drips. Put the sugar, unsweetened chocolate, butter and 1 cup water in a saucepan. Place over medium heat and stir occasionally until all of the ingredients are melted and blended. Remove from the heat and let cool slightly, 15 to 20 minutes.
2. Sift together the flour, baking soda, baking powder and salt. In a small bowl, stir together the milk and vinegar. Grease and flour a 9-inch tube pan.
3. When the chocolate in the pan has cooled a bit, whisk in the milk mixture and eggs. In several additions and without overmixing, whisk in the dry ingredients. When the mixture is smooth, add the vanilla and whisk once or twice, to blend. "Dump" the batter into the tube pan and bake on the middle rack until a skewer inserted in the center comes out clean, about 30 minutes. Let the cake cool for 10 minutes, then remove from the pan and cool on a rackcompletely.
4. Meanwhile, melt the chocolate chips in a double boiler, then cool to room temp. Stir in the sour cream, 1/ 4 cup at a time, until the mixture is smooth. Taste some! It's good.
5. When the cake is cool, frost it. Store the cake in the refrigerator. Recipe from Judith Hesser as heard on NPR.