Start with the base: In a jar or bowl, combine oats, protein powder, cocoa powder, and a pinch of salt. Stir to evenly distribute the dry ingredients.
Add the liquids: Pour in milk and add Greek yogurt.
Mix until no dry pockets remain. If using chia seeds or vanilla, stir them in now.
Sweeten and enrich: Add maple syrup or honey and the nut butter. Stir thoroughly.
The mixture should look thick but spoonable.
Caramel swirl: Gently fold in the caramel sauce. Don’t overmix—light swirls give that Mars Bar feel.
Top it off: Sprinkle chopped chocolate over the top. Press some pieces just under the surface so they soften overnight.
Chill: Cover and refrigerate for at least 4 hours, ideally overnight, to let the oats hydrate and flavors meld.
Serve: In the morning, give it a quick stir.
If it’s too thick, add a splash of milk. Optionally add a tiny extra caramel drizzle and a pinch of flaky salt.