Chocolate Chip Crumb Bars

Crust & Topping:
1 1/2 cups all-purpose flour
3/4 cup sugar
1/8 tsp salt 
3/4 cup (1 1/2 sticks) butter, chilled

2 eggs
1/2 cup brown sugar
1/2 cup white sugar
1/2 cup sour cream 
6 tbsp flour
pinch of salt
1/2 tsp vanilla extract
1 cup milk chocolate chips, plus 1 tbsp flour


For crust/topping: Preheat the oven to 350 degrees.  Grease a 9x9 inch baking pan. Combine the flour, sugar, and salt in a medium bowl. Cut the butter into 1/2-inch cubes, and add to the flour mixture. Using a fork for pastry cutter, cut the butter in until mixture resembles coarse crumbs.  Reserve 3/4 cup of the mixture to use as the topping.  Press the remaining mixture into the bottom of the pan, and bake for 10-12 minutes.  Cool for 10-15 minutes.

For filling: Whisk the eggs in a large bowl, then add the white and brown sugar, sour cream, flour, salt and vanilla extract.  Toss the chocolate chips with the tablespoon of flour, this helps prevent the chips from sinking to the bottom. Gently fold the chocolate chips into the batter and pour the mixture over the crust. Scatter the remaining flour mixture evenly over the filling, and bake 35-45 minutes.

Cool for 1 hour before cutting into bars.