Preheat oven to 350 degrees.
Combine flour, collagen, baking powder, baking soda, cinnamon, and salt in a medium bowl.
Blend bananas, eggs, dates, coconut oil, and vanilla in a food processor until smooth. Transfer this liquid mixture into a large mixing bowl.
In the large mixing bowl, stir dry ingredients into wet ingredients and mix until just combined. Fold in nuts or add-ins.
Grease or line one standard 8.5" x 4.5" loaf pan OR two mini 5.75" x 3” loaf pans with parchment paper.**
Pour dough into pan. The pan should be about 3/4 way full with batter. Bake 8.5" x 4.5" loaf pan for 40-50 minutes OR mini 5.75" x 3” loaf pans for 30-40 minutes, or until browned and baked through.
Let cool slightly then remove from the pan. Store in an airtight container for up to 1 week or freeze loaves for up to 4 months.