Preheat the oven to 350 degrees F and coat an 8x8 pan with nonstick spray.
Add all ingredients to a medium bowl and stir together to combine thoroughly, but gently.
Place batter into prepared and smooth with a spatula so the batter is evenly distributed in the pan.
Bake for 20-24 minutes or until lightly golden brown around the edges and a cake tester inserted into the middle comes out cleanly.
Remove from oven, place pan on a wire rack and allow to cool completely before slicing.
Serve warm, at room temp, or chilled.
Notes
Let cool and store in an airtight container at room temperature for 3 days or in the fridge for up to 5. Serve cold or warm briefly in the microwave. You can also store in the freezer for up 3 months. Thaw in the fridge or at room temperature.
Egg-free: Grind the oats in a food processor or blender before you add them to the batter to create more of a flour-like consistency or use purchased oat flour. And omit the eggs and add 1 tablespoon ground flaxseeds and 1/4 cup milk.
You can omit the flaxseed if you don't have it. Just be sure to let it cool fully as it will be a little more tender.
To make these with less added sugar: Use unsweetened dried fruit (such as raisins) instead of chocolate chips.
Cut into smaller pieces for your child if needed.
Top with nut butter, cream cheese, or apple butter if desired.