In a bowl mix milk, yogurt, egg and lemon juice until mixture starts to thicken. Stir in blueberries. Cover and chill at least 2 hours. Use as pudding topped with additional berries or as a filling for crepes or torte. Blueberry Torte: Split two 7-inch sponge or yellow cake layers in half horizontally. Assemble torte by spreading pudding between split layers and on top layer. If desired, garnish with additional blueberries or whipped cream.