Watermelon Smoothie Bowl. My thick watermelon smoothie bowl is made with just 3 ingredients! All you need is frozen watermelon, frozen strawberries, and kefir! How to make- In your blender, add 2 cups frozen strawberries, 2 cups frozen watermelon, 1/4 cup plain kefir. Add the lid and turn your blender on low. Use the tamper to push the frozen fruit down towards the blades. Keep blending until the mixture is smooth and creamy. Healthy! Gluten Free! Dairy Free (option)!