Healthy Banana Blackberry Muffins (just 5 ingredients!)

Ingredients

• 225 g Oats ((2 ¼ cups))
• 2 tsp Baking Powder
• ¼ tsp Salt ((optional))
• 400 g Ripe Banana ((4 medium bananas - 2 cups))
• 80 ml Water ((⅓ cup))
• 300 g Blackberries ((2-3 cups))
• 1 tsp Vanilla Extract ((optional))