Add bananas, eggs, rolled oats, cinnamon, ground flax seed, and vanilla extract (all ingredients except for walnuts) to a large mixing bowl
Blend with a hand mixer on low speed until well combined
Preheat skillet on medium low, then brush with a little olive oil to prevent sticking
Add pancake batter to skillet, dividing to make 6-8 small pancakes (only cook a few pancakes at a time)
Sprinkle tops with chopped walnuts while bottom side cooks
Flip after 4-5 minutes (pancakes should flip easily) and cook the other side another 4 minutes, or until pancakes are cooked through
Repeat steps 4-6 for remaining batter
Serve plain or topped with peanut butter, honey, applesauce, or whatever you like!