Line an 8×8-inch baking dish with parchment paper, leaving some overhang on the sides. This makes it incredibly easy to lift the bars out cleanly after chilling. Lightly spray the parchment with non-stick cooking spray for extra insurance.

In a large mixing bowl, combine the rolled oats, protein powder, chia seeds, and sea salt. Stir everything together until the dry ingredients are evenly distributed. This step ensures no pockets of protein powder remain in the finished bars.

In a separate microwave-safe bowl, mix together the peanut butter, honey (or maple syrup), and vanilla extract. Microwave for 20–30 seconds, then stir until smooth and fully combined. The mixture should be pourable and glossy.

Pour the wet mixture over the dry ingredients. Stir vigorously until everything is thoroughly coated and no dry spots remain. If the mixture feels too crumbly, add milk one tablespoon at a time until it holds together when pressed between your fingers.

Allow the mixture to cool slightly before folding in the mini chocolate chips. Adding them too soon while the mixture is warm will cause them to melt and lose their shape. Stir gently to distribute them evenly throughout.

Transfer the mixture into your prepared pan. Use the back of a spatula or the bottom of a flat glass to press the mixture down firmly and evenly. The more firmly you press, the better the bars will hold together. Refrigerate for at least 30 minutes before cutting.

Once chilled and firm, lift the slab out using the parchment overhang. Place it on a cutting board and slice into 10–12 even bars. Serve immediately or store for later — either way, they’re absolutely delicious.