Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch baking pan.
In a medium bowl, combine 1 1/2 cups flour, baking powder, baking soda, and salt. In a large bowl, cream 1/2 cup butter and 1 cup sugar until light and fluffy. Beat in eggs one at a time, then stir in vanilla. Beat in the flour mixture alternately with the orange juice and sour cream. Spread batter into prepared pan.
In a small bowl, combine 1/2 cup melted butter and 1/3 cup sugar. Stir in 1/2 cup flour until crumbly. Sprinkle over the top of the cake.
Bake in preheated oven for 30 to 35 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow cake to cool before serving.
Interesting Facts
The Screwdriver Cake is named after the popular alcoholic cocktail. It gets its citrus flavor from orange juice.
The crumb topping is made from melted butter, sugar, and flour. It gives the cake a crunchy texture and a buttery flavor.
The Screwdriver Cake is an American classic that is sure to be a hit at any gathering.