Place water in a medium saucepan and sprinkle gelatin over the top. Let sit for 10 minutes. Add sugar and salt. Heat mixture over medium, stirring frequently, until the sugar dissolves. Add lingonberries and remove from heat. Transfer mixture to a blender and puree until smooth.
Whisk lingonberry mixture with vanilla and sour cream (or greek yogurt or skyr) in a large bowl until fully combined. Set aside. Whip cream to medium peaks in a mixer. Gently whisk cream into lingonberry mixture until fully combined.
Pour mousse into individual serving cups and chill at least two hours. Serve, garnished with lingonberries.
Frozen lingonberries are available at some grocery and Scandinavian specialty stores, particularly if you live in an area with a strong Scandinavian heritage. They can also be ordered online through www.sturdiwheat.com or www.nwwildfoods.com. You can substitute a 14.5 ounce jar of lingonberry jam for the frozen lingonberries. Should you choose to go that route, simply reduce the sugar to ¼ cup and add the full jar of preserves to the saucepan with the water and gelatin in step 1 in place of the lingonberries.
Calories: 291kcal | Carbohydrates: 35g | Protein: 6g | Fat: 15g | Saturated Fat: 9g | Cholesterol: 56mg | Sodium: 31mg | Potassium: 77mg | Sugar: 26g | Vitamin A: 636IU | Vitamin C: 13mg | Calcium: 78mg | Iron: 1mg