Apple Cake Bars

1 cup white spelt flour or all-purpose flour
1 teaspoon cinnamon
1/2 teaspoon baking powder
1/2 teaspoon sea salt
1/4 teaspoon baking soda
1 cup cane sugar
1 stick (1/2 cup) butter, melted
1 large egg
1/2 cup chopped walnuts or pecans
2 large sweet apples, peeled, cored, cut into 1/2-inch dice

1. Heat oven to 350°F. Grease an 8-by-11-inch baking dish. 
2. Stir together flour, cinnamon, baking powder, salt, and baking soda in a bowl.
3. In a separate bowl, beat together butter, sugar, and egg with a mixer for 2 minutes. Stir in walnuts and apples. Add flour mixture, and stir until combined. 
4. Spread batter in pan and bake until golden brown, about 45 minutes. Cool at least 30 minutes before cutting.