Peel, core and slice 2 pounds tart apples into ¼-inch-thick slices. Place in a large bowl. Add ½ cup packed brown sugar and 2 teaspoons ground cinnamon. Toss to combine and coat the apple slices.
Melt 2 tablespoons unsalted butter in a large skillet over medium heat. Add the apple mixture cook, stirring often, until the brown sugar begins to melt.
Place 2 tablespoons water and 2 teaspoons cornstarch in a small bowl and stir until the cornstarch is dissolved, then pour over the apples.
Continue to cook, stirring often, until the apples are tender and the cinnamon sugar coating has thickened slightly, about 8 minutes.
Remove the pan from the heat. Add 1 teaspoon vanilla extract and stir to combine. Serve warm.
