Preheat oven 180c/350f

13×9” Pan-greased

Prepare Crumb Topping:

1cup dark brown sugar

½ cup light brown sugar

2 tablespoons cinnamon

½ teaspoon sea salt

2 sticks butter- melted

2 ½ cups King Arthur Gluten Free All Purpose Flour+ 1/3 cup extra if needed

Mix flours and sugars together. Add butter. Using your hands, toss gently. Your objective is big clumps. If mixture is too wet, add additional  1/3 cup of flour. Squeeze into clumps if needed. Set aside.

Prepare Batter

Combine dry ingredients in a small bowl:

2 ½ cups King Arthur Gluten Free Flour

1 ½ teaspoons baking soda

1teaspoon baking powder

½ teaspoon sea salt

Set aside.

1 ½ sticks butter-room temp

3 tablespoons cream cheese- room temp

1 ½ cups brown sugar

3 eggs

1teaspoon vanilla

1 ½ cups sour cream

Beat butter and cream cheese until light and fluffy. Add sugars and beat for another minute. Add eggs one at a time beating well after each addition.

Add in vanilla and sour cream. Combine.

Add half the flour mixture. Beat until combined. Repeat with remaining half flour mixture.

Pour into greased pan and

Cover batter with topping. Be mindful not to crush your big crumbs while doing this step.

Bake for 35-40 minutes

Cool or 20 minutes before cutting into squares.

Sprinkle top with powdered sugar (icing sugar) just before serving.