Preheat your oven to 375°F and grab an 8x8-inch baking dish. I like to lightly butter it so nothing sticks. This makes cleanup way easier and prevents those burnt edges that nobody enjoys.

Whisk together the egg and milk in a small bowl until combined. Pour this mixture into your baking dish, then scatter the blueberries on top. The egg and milk create a custard-like base that's honestly magical.

In a separate bowl, combine the oats, whole wheat flour, brown sugar, and lemon zest. Mix everything until it's evenly distributed and you don't see dry flour pockets. This is where the magic happens for your cozy summer baking masterpiece.

Cut the cold butter into small pieces and add it to the dry mixture. Use your fingertips to work it in until it looks like coarse sand with some pea-sized chunks. I accidentally doubled the garlic once and it was even better — okay, wrong recipe, but you get the point about not being too precious with measurements.

Sprinkle the cinnamon and nutmeg over the oat mixture and gently toss to combine. Spread this topping evenly over the blueberries and custard base. Don't pack it down — you want it to stay crumbly and crisp.

Bake for 35 to 40 minutes until the topping turns golden brown and the filling bubbles slightly around the edges. You'll hear it sizzle a little when it's getting close. Mine always sticks a little to the pan and that's completely fine.

Let it cool for 10 minutes before serving — I know it's hard to wait. The crisp will set up slightly and be way easier to scoop without falling apart everywhere.