Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch pan.
Prepare the topping by mixing together the brown sugar, cinnamon, nutmeg, and chopped pecans.
Sift together the flour, baking powder, baking soda, and salt.
Beat butter and sugar together in a large bowl with an electric mixer until light and fluffy; add eggs one at a time, thoroughly beating each egg into the butter mixture before adding the next. Add apple butter, vanilla, and wheat germ or bran cereal. Add sifted dry ingredients alternately with sour cream; mix well after each addition.
Pour half the batter into the prepared pan; sprinkle with half of the topping. Pour remaining batter into pan and top with the rest of the topping.
Bake in the preheated oven until a tester inserted in the center comes out clean, about 40 minutes.