Coffee Cake with Raspberries & Hazelnut Crumble

Here is a delicious recipe for coffee cake. I found the original online, and then altered it to suit my needs. This is definitely more of an occasional treat, with all the butter and sugar, but so yummy I had to share!

Coffee Cake with Raspberries & Hazelnut Crumble
Batter
1 cup butter, softened
2 cups raw sugar
2 eggs
1 cup plain (nonfat) Greek yogurt
1 tsp. pure vanilla extract
1 3/4 cups whole wheat pastry flour
1/4 cup flax seed meal (optional, you can use an additional 1/4 cup of the flour instead)
1 tsp baking powder
1/8 tsp sea salt

Topping
1/3 cup whole wheat pastry flour
1/2 cup packed brown sugar
2 Tbsp. melted butter
1 tsp. ground cinnamon
1/4 tsp. freshly grated nutmeg
1/3 cup chopped hazelnuts

Filling
1 1/2-2 cups raspberries (if frozen, thaw and drain first)

Directions
Preheat oven to 350 degrees F. Grease a 9x13 pan and set aside.
Cream together the butter and sugar until light and fluffy. Add the vanilla and eggs, mix well, then add in Greek yogurt. Mix in the flour, baking powder, and salt, stirring until well mixed.
Spread half the mixture in the baking pan, top with a layer of raspberries, then the remaining batter.
Mix together, in another bowl, the topping ingredients. When well mixed, spread over the top of the coffee cake.
Bake for 35 to 40 minutes in preheated oven, or until a toothpick inserted near the center comes out clean. Best served slightly warm!