Walnut Cinnamon Muffins (Lactation-friendly)

• 3 cup plain rolled oats
• 1 tsp cinnamon
• 2 tsp baking powder
• 0.5 tsp salt
• 1 cup walnuts, chopped
• 1.5 tbsp brewers yeast
• 1.5 tbsp flax meal (ground flax seeds)
• 0.5 cup brown sugar
• 1 cup banana, mashed (2-3 ripe bananas)
• 2 eggs
• 1.5 cup milk