Preparation Preheat oven to 350° F / 176° CGrease standard muffin pan or line with 12 paper muffin cup linersIn a large mixing bowl combine gluten-free flour blend, tapioca flour, sweet rice flour, guar gum OR xanthan gum, baking powder and salt. Use a large whisk to thoroughly combine.Add coconut milk or milk, egg, melted shortening and vanilla. Stir to blend.Add the diced rhubarb and sliced strawberries. Stir to blend. Fill muffin cups about 2/3 full. Bake in preheated oven for about 20-25 minutes, or until a toothpick inserted in the center comes out clean.Reminder: Always make sure your work surfaces, utensils, pans and tools are free of gluten. Always read product labels. Manufacturers can change product formulations without notice. When in doubt, do not buy or use a product before contacting the manufacturer for verification that the product is free of gluten.