Preheat the oven to 200 degrees F.  Combine the strawberries, sugar, and lemon juice in a small saucepan and allow to marinate for 10 minutes.  Bring the mixture to a gentle simmer over medium-low heat stirring frequently.
Transfer the mixture to a rimmed baking sheet and bake, stirring every 20 minutes until it is thick and jam-like, about 2 hours.  Preserves can be made ahead, stored in an airtight container, and refrigerated for up to 1 week, or frozen for several months.

Makes 1 ¼ cups.