Prepare a heavy loaf pan (glass or stoneware) by lining with parchment. Preheat the oven to 350 degrees F. In a bowl, whisk 1/2 cup rice flour and rest of the dry ingredients and set aside. Add spices like 1/2 tsp cinnamon for additional flavor if you like.
In another bowl, add all the wet ingredients and mix well. If they are not at room temperature, let the mixture sit for a few minutes to warm up, then whisk really well until the sugar and nut butter are well combined.
Combine the wet and the dry and whisk well to make a smooth batter. Transfer half of the mixture to another bowl.
To one bowl, add cocoa powder and whisk in lightly to just about combine. You can also add 2-3 tbsp chocolate chips for additional chocolateyness.
To the other bowl add 1 tbsp rice flour and whisk in lightly.
Add layers of the batters as you wish to the lined loaf pan (or add ladles of the batter and swirl lightly). I added nut butter layer, then chocolate and then nut butter. Sprinkle some chocolate chips on top.
Bake for 40 to 45 minutes or until a toothpick from the center comes out clean. Cool for 5 minutes, then carefully lift from the pan. Do not let the cake sit in the hot pan for too long. Lightly cover with a kitchen towel or parchment and let it cool completely before slicing. Store on the counter for the day, refrigerated for upto a week. Warm to serve.
Notes
Use any nut butter or sun butter in the cake.Nutrition is 1 of 6 serves (about 2 slices)