How to Make It
Preheat oven to 350°.
To prepare cake, weigh or lightly spoon flour into dry measuring cups; level with a knife. Combine flour, baking powder, cinnamon, and salt in a small bowl, stirring with a whisk.
Combine brown sugar, 1/4 cup butter, and 1 teaspoon vanilla in a large bowl; beat with a mixer at medium speed until well combined. Add eggs, 1 at a time, to sugar mixture; beat well after each addition. Add pumpkin; mix well. Fold in flour mixture. Spread batter into a 13 x 9-inch baking pan coated with cooking spray. Bake at 350° for 25 minutes or until a wooden pick inserted into the center comes out clean. Cool completely in pan on a wire rack.
To prepare the frosting, combine 2 tablespoons butter, 1/2 teaspoon vanilla, and cream cheese in a medium bowl; beat with a mixer at medium speed until combined. Gradually add the powdered sugar, beating until well combined. Spread frosting evenly over top of cake.