Preheat and prep: Heat the oven to 350°F (175°C). Line a baking sheet with parchment paper.
Mix the dry ingredients: In a medium bowl, whisk oats, flour, baking soda, baking powder, salt, and cinnamon until combined.
Whisk the wet ingredients: In a large bowl, whisk melted oil, melted butter, coconut sugar, and maple syrup until glossy.
Add the egg and vanilla, and whisk until smooth. Stir in the Greek yogurt until fully incorporated.
Combine: Add the dry mixture to the wet. Use a spatula to fold until just combined.
The dough will be thick and slightly sticky.
Add the mix-ins: Fold in chocolate chips and nuts (if using). Do not overmix.
Scoop: Use a medium cookie scoop (about 1 1/2 tablespoons) to portion dough onto the baking sheet, spacing about 2 inches apart. Press a few extra chocolate chips on top for that bakery look.
Shape for texture: Lightly flatten each mound with your fingertips to about 3/4-inch thick.
This helps them spread evenly and bake up chewy.
Bake: Bake for 9–12 minutes, until the edges are set and the centers look slightly underbaked. They’ll firm up as they cool.
Finish: Let cookies cool on the sheet for 5 minutes, then transfer to a rack. For a pro finish, gently nudge the edges with a round cookie cutter right after baking to make them perfectly round.