Greek Yogurt with Warm Berry Sauce

⅔ cup frozen blueberries ⅔ cup frozen blackberries ½ cup water ¼ cup sugar 2 tablespoons fresh lemon juice 1 tablespoon butter 2 cups plain 2% Greek yogurt

Combine first 5 ingredients in a small saucepan. Bring mixture to a boil. Reduce heat to medium-low; gently boil 10 minutes or until sauce thickens. Stir in butter. Spoon ½ cup yogurt into each of 4 bowls or short glasses; top each serving with about ¼ cup sauce. Serve immediately.