Step 1

Preheat oven to 350°F (177°C). Generously spray a muffin pan with nonstick spray. If using muffin liners, spray them with nonstick spray. The oatmeal cups stick to the liners a bit regardless, so I recommend skipping them.

Step 2

Whisk all of the ingredients together, except for the apples (and nuts and coarse sugar), in 1 large bowl. Using a spoon or rubber spatula, fold in the apples and nuts (if using). Batter will be a little liquid-y. Spoon batter evenly into muffin cups, making sure both the oats/apples and liquid are in each. Fill all the way to the top. See photo above. If desired, sprinkle the tops with coarse sugar.

Step 3

Bake for 25-30 minutes or until the edges are lightly browned and top appears set. If the tops appear to brown very quickly, tent a piece of aluminum foil on top.

Step 4

Cool for 5 minutes before serving. Cover leftover oatmeal cups tightly and refrigerate for up to 1 week.