Dice the apple: Cut 1 small apple into tiny cubes.
Smaller pieces mix better and soften slightly overnight. If you like a tart edge, leave the skin on for extra fiber.
Season the fruit: Toss the apple with a squeeze of lemon juice, 1/2 teaspoon cinnamon, and a small pinch of nutmeg. Add a pinch of allspice or cloves if you want a deeper pie flavor.
Mix the dry base: In a jar or bowl, add 1/2 cup rolled oats, 1 tablespoon chia seeds (optional), and a tiny pinch of salt.
Stir to distribute the seeds and salt evenly.
Add protein and dairy: Stir in 1/2 cup plain Greek yogurt and 1 scoop protein powder. Tip: If your protein powder is very sweet, reduce the maple syrup later.
Sweeten and flavor: Add 1/2 to 3/4 cup milk, 1 to 2 teaspoons maple syrup, and 1/2 teaspoon vanilla extract. Mix well until no dry clumps remain. Adjust milk for your preferred thickness.
Fold in the apples: Add the spiced apple pieces and stir.
If using raisins, add a small handful now so they plump overnight.
Chill overnight: Cover and refrigerate at least 4 hours, but ideally overnight, to let the oats hydrate and flavors meld.
Finish and serve: In the morning, give it a good stir. Top with chopped walnuts or pecans for crunch. Add a splash of milk if it’s too thick, or extra cinnamon if you want more spice.