Preheat the oven to 350°F.
Grease a 12-muffin pan with an oil of choice, or use paper liners
Put the oats, salt, and baking soda in the bowl of a food processor or blender. Process them into an even-textured flour.
Add in the eggs, bananas, lemon zest if using, and vanilla and process until smooth.
Add the almond flour and process until well-combined.
Pour or spoon some batter into each muffin cup, filling them halfway. Sprinkle a few blueberries in each cup, then distribute the rest of the batter. Top the muffins with the remaining blueberries, gently pressing them into the batter to anchor them.
Bake for about 30 minutes, or until golden brown and a toothpick inserted into the middle comes out clean.
Allow to cool for about 10 minutes before removing from the pan.