Add the cottage cheese to a blender or food processor and blend until it becomes completely smooth and creamy, with no visible curds. Pause and scrape down the sides if needed, then blend again until the texture looks silky, as this step is key to avoiding a grainy texture in the finished bars.

Transfer the blended cottage cheese to a large mixing bowl. Add the eggs, maple syrup, and vanilla extract, then whisk everything together until the mixture is smooth, well combined, and slightly glossy, making sure the eggs are fully incorporated.

Add the oats, protein powder, cinnamon, baking powder, and salt to the bowl. Using a spatula or wooden spoon, gently mix until the dry ingredients are just incorporated into the wet mixture. Avoid overmixing at this stage to keep the bars tender and moist.

Gently fold in the diced apples, stirring just enough to distribute them evenly throughout the batter without breaking them down. This helps keep small apple pieces intact so they add natural sweetness and texture in every bite.

Pour the batter into a parchment-lined baking dish and use a spatula to spread it out evenly, smoothing the top so the bars bake uniformly. Tap the pan lightly on the counter to release any air bubbles.

Place the dish in the oven and bake until the center is set and the edges are lightly golden. A toothpick inserted near the center should come out mostly clean, with just a few moist crumbs attached.

Remove the baking dish from the oven and allow the bars to cool completely in the pan. Letting them cool fully helps them firm up, making them easier to slice cleanly into neat, even bars.