Lemon Oat Crumble Bars

           8 tablespoons butter; softened
           3/4 cup brown sugar; packed
           1 teaspoon vanilla
           1 cup flour
           1 teaspoon baking powder
           1/4 teaspoon salt
           1 cup old-fashioned oats
           14 ounces sweetened condensed milk
           2 lemons; juiced; zest from 1

           Preheat oven to 350°. Line an 8x8 pan with parchment.
           
           In a mixing bowl cream butter and sugar. Add vanilla
           and mix until combined. Add flour, powder and salt;
           mix until combined. Add oats and stir until combined.
           Place 2 cups of mixture in prepared pan; pat down.
           Bake for 12 minutes.
           In a mixing bowl whisk together milk, lemon juice and 
           zest. Pour mixture over the crust while still hot; spread 
           it evenly. Sprinkle remaining oat mixture evenly over
           the filling. Bake for 22-25 minutes, until the center is set.