Preheat oven to 350 and spray a 13×9 pan with cooking spray.
Add 2 cups flour, brown sugar and cinnamon to food processor and pulse until combined. Cut butter into one inch pieces and add to processor. Process until crumbly. Set aside.
Put 1/2 cup soft butter, sugar, eggs and vanilla in mixing bowl. Mix until well blended.
Mix together 4 cups flour and the baking powder. Add flour mixture and orange juice alternately to butter mixture until well combined.
Pour batter into greased 13/9 inch baking dish. Top with crumb mixture.
Bake for one hour or until toothpick comes out clean.
Cool completely and cut into squares. Serve with ice cold orange juice!
Notes
Orange Juice: You can use any kind you have on hand, either with or without pulp. (We are very partial to Trader Joe’s OJ these days!)
Butter: Either salted or unsalted is fine.
Baking Powder: Make sure your baking powder is up to date (you can find the expiration date on the box)…it is the ingredients that gives this cake its fluffiness!