Preheat the oven to 350 degrees F and spray or oil a muffin tray (or use muffin papers).

Add the oats to a blender and blend until a flour forms. It’s okay if it doesn’t reach the consistency of regular flour. I often leave mine somewhat coarse and it turns out great.

Add the remaining ingredients except for the walnuts (and chocolate chips if you’re adding them) and blend until smooth.

Stir in the walnuts (and chocolate chips if adding).

Fill the muffin holes ⅔ of the way up (the muffins will rise!) and if desired, top with more walnuts, chocolate chips, and/or oats.

Bake on the center rack of the preheated oven for 20 to 25 minutes, or until muffins are golden-brown and feel firm when gently poked.

Allow muffins to cool at least 30 minutes before running a butter knife along the edge of the muffin between the muffin and the tray to release the muffins.