Heat oven to 375 degrees F. Grease 12 muffin tin wells or line with paper cups.
In a large bowl, mix avocado, bananas, eggs and milk. In a separate bowl, whisk or sift together flour, sugar, baking soda and salt. Stir into avocado mixture; do not over-mix. Stir in walnuts.
Spoon batter into prepared muffin tin; bake 15 to 20 minutes or until tops start to brown and a toothpick inserted into a muffin comes out clean.
