Preheat oven to 350 degrees F. In a medium bowl combine 1 cup flour, 3 Tbsp. granulated sugar, and the cinnamon. Use a pastry blender to cut in the 1/3 cup cold butter until mixture resembles fine crumbs and starts to cling together. Pat into the bottom of a 9-inch square baking pan. Bake 5 minutes or just until set.
In a large bowl beat the 3/4 cup softened butter with a mixer on medium 30 seconds. Add the 3/4 cup granulated sugar and beat until combined. Beat in egg and maple syrup. Add 1 cup flour and half-and-half alternately, beating on low after each addition just until combined (batter may appear slightly curdled). Pour into crust-lined baking pan.
Bake about 35 minutes or until the cake is nearly firm when you gently shake it. Cool in pan on a wire rack. If desired, sift powdered sugar over top and serve with additional maple syrup.