Zucchini, Banana, and Flaxseed Muffins

INGREDIENTS

• Nonstick cooking spray
• 1 3/4 cups all-purpose flour (spooned and leveled)
• 1/2 cup ground flaxseed
• 1 cup lightly packed light-brown sugar
• 2 teaspoons baking soda
• 1 teaspoon baking powder
• 1/2 teaspoon coarse salt
• 1 teaspoon ground cinnamon
• 1 1/2 cups coarsely grated zucchini (from 1 large zucchini)
• 1/3 cup mashed ripe banana (from 1 large banana)
• 3/4 cup whole milk
• 1 large egg, lightly beaten
• 1 teaspoon pure vanilla extract