Cream butter and sugar until light and fluffy.
Add eggs and sour cream; mix well.
Combine flour, baking powder, soda, salt and nutmeg.
Add to batter, and mix well.
Pour batter into greased and floured 9x13-inch baking pan.
Combine brown sugar, pecans and cinnamon; mix well.
Sprinkle 1/2 of this mixture over cake batter; swirl mixture through batter.
Sprinkle remaining 1/2 mixture evenly over cake batter.
Cover and chill ovenight.
Uncover and bake in preheated 350 degree oven oven for 35 to 45 minutes, or until cake tests done with a toothpick.