Begin my sifting the dry ingredients in a small mixing bowl including the flour, cocoa powder, baking powder, baking soda, and salt. Set aside for later.
In a separate mixing bowl add in the oat milk, olive oil, white sugar, brown sugar, and applesauce. Gently mix together to combine. Then, add in the sifted dry ingredients and mix together just until any large streaks of flour are gone. DO NOT overmix.
Lastly, add in the chocolate chips and fold them in with a spatula or very gently mix them in. I like to set aside a few chocolate chips to put on top of my batter, but that is optional.
Fill a muffin pan with 4-5 cupcake liners and fill them to the very top with batter. Sprinkle on any chocolate chips you set aside at this time. Then, let the muffin batter rest for 30 minutes- 1 hour before baking. While letting the batter rest isn't 100% necessary, it will allow the batter to rise more and lead to more "bakery-style" muffins. If you want to skip this the muffins will still taste great.
Towards the end of letting the batter rest, preheat the oven to 375F. Then, add the muffins to the oven and bake for 16-18 minutes until cooked through. Try not to open the oven door to check on the muffins or they may deflate and just check them with an oven light.
Remove and serve warm!