01 - Preheat oven to 350°F. Grease or line an 8x8-inch baking pan with parchment paper.
02 - In a large bowl, mix together rolled oats, vanilla protein powder, baking powder, ground cinnamon, and salt until evenly distributed.
03 - In a separate bowl, whisk milk, eggs, honey or maple syrup, unsweetened applesauce, melted coconut oil or unsalted butter, and vanilla extract until smooth.
04 - Pour wet mixture into the bowl of dry ingredients, stirring gently until just combined.
05 - Fold mini chocolate chips or dried fruit and chopped nuts into the batter, if using.
06 - Spread batter evenly in prepared pan.
07 - Bake for 22–25 minutes, or until set and lightly golden on top.
08 - Allow to cool completely in the pan before slicing into 9 squares.