Preheat oven to 375 degrees and line a muffin tin with cupcake liners or grease the muffin tin.
In a food processor or blender, blend together the cooked lentils, banana, oil, egg, maple syrup, dates, and vanilla until smooth.
Add the dry ingredients (oats, flour, baking soda, and cinnamon) and process until just mixed together. Don't over-process.
Add in any optional add-ins such as blueberries, chopped strawberries, or chocolate chips.
Scoop batter into the muffin tins and fill them up about 3/4 of the way.
Bake in over for 18 minutes or until a toothpick inserted into the center comes out clean.
Serve immediately or store fridge for 4 days or freeze up to 3 months.