Preheat your oven to 375 degrees.
In a large bowl, combine your apple slices, lemon juice, cinnamon, all spice, granulated sugar, and brown sugar. Melt 2 tbsp of the unsalted butter in a medium skillet on medium heat. Once melted, add in your spiced apples and cook, stirring occasionally. Continue until the apples are softened, but still maintain their form, about 10 minutes.
Using a slotted spoon, transfer your apples to a pie dish, leaving the juices behind in the skillet. Set apples to the side for now. Your skillet should have a decent amount of juices remaining in it. Turn the heat up to medium high, and bring to a slow boil while stirring constantly. The juice is full of sugar, so be careful not to let it get too hot or it will burn. You are wanting the juices to reduce to 1/3 of what it originally was, thickening into a caramel sauce. This should take about 5 minutes.
Once your reduction has thickened to the right consistency, carefully pour over your apples.
Melt the remaining 2 tbsp of butter in the microwave using a microwave safe dish. Place your granola into a medium sized bowl and pour the melted butter over your granola. Stir until the granola is coated sufficiently
Sprinkle the granola over your caramel apples and place your pie dish in the oven. Bake until the granola is golden brown on top, about 10 minutes.
Serve warm by itself or topped with vanilla ice cream.
