Query: Can I assemble the oatmeal the night before I plan to serve it?
Context: The oats tend to soak up the liquid ingredients when stored in the refrigerator overnight, which isn't ideal. For a shortcut in the morning, instead, I recommend preparing the blueberries and lemon zest, then cover and refrigerate. Combine the dry ingredients and store them in a small container. Blend the liquid ingredients, cover and store overnight in the refrigerator. In the morning you can quickly assemble the ingredients according to the recipe and bake. Another option is to bake it in advance, cool then cover the baking dish and refrigerate overnight. You can heat it up in the morning, either by warming up individual servings in the microwave or reheating the entire dish at 300°F for 20 minutes or until it reaches a warm serving temperature.