How to Make It
Preheat oven to 350°.
Weigh or lightly spoon flours into dry measuring cups; level with a knife. Combine flours, xanthan gum, baking powder, and salt in a medium bowl; stir with a whisk. Make a well in center of mixture. Combine 3/4 cup sugar, 1/4 cup melted butter, and next 3 ingredients (through egg); add to flour mixture, stirring with a whisk until blended.
Pour batter into a 9-inch round cake pan coated with cooking spray. Combine 1 tablespoon sugar, 1 tablespoon melted butter, and almonds in a small bowl; sprinkle over batter. Bake at 350° for 30 minutes or until edges are lightly browned and a wooden pick inserted in center comes out clean. Cool completely in pan on a wire rack.