Sift together flour and baking powder. Add the flour mix to the mixer in 3 batches on low speed, alternating between adding the flour and buttermilk. Mix until everything is combined but make sure not to overmix.

Beat the butter and sugar together until light and fluffy. Beat in the eggs, one at a time, then the cinnamon, vanilla, and salt. Mix the cocoa, red coloring, and water, and add to the creamed mixture.

Dissolve the soda in the vinegar and fold into the cake batter very carefully. Turn into two 9-inch greased and toured cake pans (or, if you like, grease the pans and then fit the bottoms with greased paper). Do not flour the pans heavily.

Bake in a preheated 350°F oven 25 to 30 minutes or until the cake springs back when pressed lightly in the center. Let cool in the pans on a rack for several minutes, then loosen and turn out onto the rack to cool.

When cool, frost with white fluffy frosting, or use the white velvet icing, which is not excessively sweet.