Preheat the oven to 350° Fahrenheit. Grease a 9x13inch pan with butter or cooking spray, set aside. In a large bowl, using an electric mixer, cream together the butter and brown sugar until lighter and fluffy (about 2-3 minutes). Add in the egg, vanilla, and pumpkin and blend.

In a smaller bowl, whisk together all of the dry ingredients (flour, almond meal, baking powder and soda, salt, spices) until combined, then add to the pumpkin mixture, and blend until well-mixed. Dump in the chocolate chunks and use a spatula to stir until combined. Pour batter into the prepared pan and smooth until it is even. Bake for 35-40 minutes or until a knife inserted in the middle comes out clean.