Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch pan.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla.
Combine the flour, baking powder, baking soda and salt; stir into the creamed mixture alternately with the sour cream. Spread batter into the prepared pan.
In a small bowl, mix together the pecans, brown sugar and cinnamon; sprinkle over the top of the batter.
Bake at 350 degrees F (175 degrees C) for 35 to 40 minutes, or until golden brown. Let cool in pan before serving.
Interesting Facts
The original recipe for coffee cake dates back to the 1700s.
Coffee cake is traditionally served with coffee.
Pecans are native to North America and have been used for centuries in baking.