Best Coffee Cake EVER

I think this is a Martha Stewart recipe, but I'm not positive. I found it online at some point and it's my go-to coffee cake recipe!

2 c flour
1 T baking powder
3/4 c white sugar
1/2 tsp salt
1 stick butter
3/4 c milk
1 egg
2 T melted butter
2 T white sugar
2 tsp each cinnamon and nutmeg

1. Whisk together flour, baking powder, sugar and salt.
2. Cut in butter using pastry blender, until mixture resembles coarse crumbs.
3. Move 1/2 c of the mixture to separate bowl, and add sugar and spices (this is the topping).
4. Add milk and egg, stir gently until blended.
5. Pour batter into 8x8 greased baking dish. Top batter with melted butter, and then cover with topping.

Bake 35 minutes at 350.