Preheat oven to 350°F (177°C). Line an 8 inch by 8 inch baking pan with parchment paper leaving some overhang for easy removal later.
Add applesauce and peanut butter/almond butter to a large mixing bowl. Stir until the ingredients are fully mixed and the mixture is uniform in color. Add in oats and stir until they are evenly mixed in. You can taste and adjust sweetness if needed. If adding any mix-ins, add them in now.
Pour batter into prepared baking pan. Use a spatula to evenly spread it across the pan and smooth the surface.
Bake for about 15-20 minutes or until the bars look set and cooked. The surface should also be dry. Let bars cool fully before removing them from the pan and cutting and serving. Store uneaten bars in an airtight container in the fridge or freezer.
