Prep the oven and pan: Preheat your oven to 375°F (190°C). Lightly grease a small baking dish, just large enough to fit your apples snugly. Add the water or apple cider to the bottom of the dish.
Core the apples: Slice a thin cap off the top of each apple.
Use a spoon or melon baller to remove the core and seeds, leaving the bottom intact. Scoop out a bit of the flesh to create a small well, about 3/4 inch wide.
Chop some apple flesh: Finely chop about 1/2 cup of the scooped apple and set it aside for the filling. This boosts the pie-like texture.
Mix the filling: In a bowl, combine oats, chopped nuts, cinnamon, nutmeg, cloves, salt, raisins, chopped apple, maple syrup, vanilla, and melted coconut oil.
Stir until everything is evenly coated and clumps slightly.
Stuff the apples: Pack the filling into each apple cavity, mounding it slightly on top. Don’t press too hard; a light pack helps the oats stay tender.
Bake: Arrange the apples in the baking dish. Cover loosely with foil and bake for 20 minutes.
Remove the foil and bake another 10–15 minutes, until the apples are tender when pierced and the tops look toasty.
Rest and serve: Let the apples cool for 5–10 minutes so the juices settle. Serve warm with a dollop of Greek yogurt or a small scoop of ice cream if you like.