Preheat your oven to 350°F (175°C) and line a small loaf pan with parchment paper for easy removal.
In a medium mixing bowl, whisk together the rolled oats, vanilla protein powder, ground cinnamon, and sea salt until well combined.
Add the almond butter, maple syrup, and liquid egg whites to the dry ingredients, stirring until a thick, cohesive dough forms.
Reserve approximately 1/4 cup of the dough for the topping, then press the remaining dough firmly into the bottom of the prepared loaf pan to create an even base.
In a separate small bowl, lightly mash half of the blueberries with the lemon juice and Greek yogurt, then fold in the remaining whole blueberries.
Spread the blueberry mixture evenly over the oat base.
Crumble the reserved dough over the top of the blueberry layer using your fingers.
Bake for 20 to 25 minutes, or until the edges are golden brown and the blueberry filling is bubbling.
Allow the bars to cool completely in the pan before slicing into squares to ensure they set properly.