Preheat oven to 350° and grease a 10-inch tube/Bundt pan.

Mix together the ¼ cup sugar and cinnamon and set aside.

Sift together the flour, baking powder and salt and set aside also.

Cream together the butter and 1 2/3 cups sugar until real fluffy. Add vanilla and eggs and beat until fluffy. Alternately add the milk and flour to the mixture.

Put a layer of dough in the cake pan (half of the batter). Sprinkle half of the cinnamon mixture over the batter, cover with remaining batter and top with remaining cinnamon mixture.

Bake for 1 hour. Cake must be thoroughly cooled before cutting.