Bring all ingredients to a light boil in a Dutch oven over medium-high heat. Reduce heat to medium-low, and simmer, stirring often, 25 to 30 minutes or until apples are tender and juices thicken. Remove and discard lemon slices. Serve warm, or let cool to room temperature (about 2 hours). Store in an airtight container in refrigerator up to 2 weeks.