Add apples, lemon juice, brown sugar, granulated sugar, cinnamon, nutmeg and salt to a heavy bottom pot. Stir together and let macerate at room temperature for about 10 minutes. Add ¾ cup of apple cider to the pot, and stir the apples one more time.

Turn the heat to medium and begin to cook the apples, stirring occasionally to make sure the apples cook evenly. Cook until the apples have softened, about 10 minutes, making sure not to cook off all of the liquid. If the liquid does cook off quickly, add ⅓ cup more apple cider to the pot.

Create a slurry by whisking together the cornstarch and remaining 2 tablespoons apple cider together in a small bowl.

Pour the cornstarch slurry into apples and stir together until dissolved. Continue cooking until the mixture is thickened, about 2-3 minutes.

Remove from heat and stir in the vanilla and butter.

Let apple mixture cool completely, and then transfer apples to a glass storage container.