Preheat the oven to 350 degrees F (175 degrees C). Line a 10-inch cast iron skillet with aluminum foil with the ends hanging over. Spray lightly with cooking spray.

Combine flour, sugar, butter, egg, almond flavoring, and salt in a bowl. Mix well. Pour batter into the prepared cast iron pan and smooth it level. Sprinkle top with almonds and sugar.

Bake in the preheated oven until lightly browned, about 40 minutes.

Cool cake in the pan for 20 minutes. Carefully lift the cake out of the pan and cool completely on a rack, about 30 minutes more. Top cooled cake with a second rack and flip over. Carefully remove foil and flip onto a serving plate. Cut and serve.