Preheat the oven to 350°F (175°C). Lightly grease a 9x13-inch baking dish or line it with parchment paper.
In a blender or food processor, pulse the cottage cheese with the eggs, melted coconut oil, maple syrup, vanilla, and lemon zest until mostly smooth but with a little texture remaining — aim for a thick, pourable mixture.
Whisk the oats, brown sugar, baking powder, and salt in a medium bowl to evenly distribute the leavening and sweetener.
Pour the blended cottage-cheese mixture into the oats and fold together with a spatula. If the batter seems very stiff, stir in the milk, 1 tablespoon at a time, until it has the texture of thick oatmeal and spreads easily.
Let the combined batter rest for 8–10 minutes at room temperature so the oats absorb some moisture — this improves structure and gives a creamier interior.
Transfer the batter to the prepared pan and smooth the top with a spatula. Scatter the blueberries evenly over the surface and sprinkle with the sliced almonds.
Bake on the middle rack for 32–35 minutes, or until the top is golden and a toothpick inserted near the center comes out with only a few moist crumbs.
Remove from oven and allow the bake to cool in the pan for about 15 minutes before slicing into 12 squares. Serve warm or at room temperature with a drizzle of maple syrup if desired.