Preheat your oven to 325 degrees. Spray a bread pan with cooking spray. (I like to line it with parchment to avoid sticking; this is optional.)
In a large bowl, combine the almond flour, sweetener, oat fiber, baking powder, xanthan gum, and salt.
In the bowl of a stand mixer, beat together the eggs, sour cream, heavy cream, banana extract, and vanilla extract.
Add the dry ingredients to the wet ingredients and beat until just combined.
If desired, stir in the pecans.
Transfer the mixture to the prepared bread pan.
Bake for 50 minutes, until a toothpick inserted into the center of the loaf comes out clean.
Let cool in the pan for 15 minutes, and then transfer to a wire rack to cool completely.