Preheat oven to 375°F. Grease 18 muffin cups or line with paper cupcake liners; set aside. Mix flour, sugar, baking powder and baking soda in large bowl. Beat eggs, milk, melted spread, banana and vanilla in medium bowl with wire whisk until smooth. Stir egg mixture into flour mixture with wooden spoon just until combined. Gently fold in blueberries and walnuts.
Evenly spoon batter into prepared pans.
Bake 20 minutes or until toothpick inserted in centers comes out clean. Cool 10 minutes on wire rack; remove from pans and cool completely.