12 tablespoons (1 1/2 sticks, 6 ounces) butter
1 3/4 cups (12 1/4 ounces) superfine or granulated sugar
1/2 teaspoon salt
1 1/2 teaspoons baking soda
2 teaspoons vanilla extract
2 cups (8 1/2 ounces) unbleached all-purpose flour
3/4 cup (2 1/4 ounces) cocoa powder
4 large eggs
1 1/2 cups (12 ounces) milk or water

In a large mixing bowl, beat together the butter, sugar, salt, baking soda, and vanilla until fluffy and light, at least 5 minutes. In a separate bowl, whisk together the flour and cocoa. If lumps remain, sift the mixture.