Cinnamon Cake

1 cube butter, softened
1 1/2 cups milk
2 eggs
2 tsp. vanilla
3 cups flour
1 cup sugar
4 tsp. baking powder
1/4 tsp. salt
*Mix together and pour into a 9X13 pan. Then mix:
1 cube melted butter
2/3 cup brown sugar
1 T. flour
1 T. cinnamon
*Pour on top of yellow mixture and swirl in using a fork. Don't mix completely. Bake at 375 for 30 minutes. Drizzle with frosting:
1/2 cube butter, softened
powdered sugar
some milk
1 tsp. vanilla
dash of salt