Preheat oven to 350 degrees Fahrenheit. Grease a 9-inch by 5-inch loaf pan with coconut oil or an oil mister and set aside.
In a large bowl, whisk together the brown rice flour, almond flour, brown sugar, coconut sugar, baking soda, baking powder, cinnamon, cloves, and salt.
In a medium bowl, whisk together the coconut oil, pumpkin, and eggs.
Pour the wet ingredients into the dry ingredients and mix with a wooden spoon or spatula until well-incorporated. The batter will be very thick.
Spread the batter evenly in the pan. Sprinkle the pepitas over the top if using. Bake until golden brown, the bread lifts away from the edges of the pan a bit, and toothpick inserted into the center comes out clean, 35-44 minutes (you may need to allow for a little more time if using butter).
Let cool in the pan on a wire rack for about 10 minutes, then remove from pan and let cool completely on a wire rack.
To store, wrap tightly with plastic wrap or foil and keep at room temperature. Keeps well for 3-4 days.