Start by peeling, coring, and slicing the apples. I love using Granny Smith apples for their tartness and firmness, but any good baking apple works. Place the sliced apples into a large mixing bowl, and toss them with lemon juice to prevent browning.

In a medium saucepan, combine the brown sugar, granulated sugar, water, cinnamon, nutmeg, ginger, and salt. Stir over medium heat until the sugar dissolves, and bring the mixture to a simmer. Add the butter and vanilla extract, stirring until smooth. Once the syrup is well-combined and simmering, it’s time to add the cornstarch slurry.

In a small bowl, mix the cornstarch with 3 tablespoons of water. Add this slurry to the simmering syrup, stirring constantly. The syrup will begin to thicken as it cooks. Continue cooking for about 2-3 minutes, until it reaches a gravy-like consistency.

Add the prepared apple slices to the thickened syrup. Stir to coat all the apples evenly. Cook for an additional 5-7 minutes, just until the apples are tender but still hold their shape. You don’t want them to be too soft since they’ll cook more during canning.

Carefully ladle the hot caramel apple filling into sterilized canning jars, leaving about ½ inch of headspace at the top. Be sure to wipe the rims of the jars with a clean cloth to remove any residue.

Place the lids and rings on the jars, tightening them just until they’re fingertip-tight. Process the jars in a boiling water bath for 25 minutes, making sure the water covers the jars by at least 1 inch. After 25 minutes, remove the jars and let them cool completely.

Once the jars have cooled, check the seals. If the lids have popped down and the jars are sealed, you’re ready to store them in a cool, dark place. Let the jars sit for 24 hours before using to ensure they’ve fully sealed.