To prepare a rosy strawberry rhubarb applesauce recipe, first you will need to prepare the ingredients for the recipe. First, you'll need the following ingredients: Strawberries, 1 cup sugar, 2 tablespoons butter, 1/2 cup water, and 1 teaspoon vanilla extract. You can also use frozen strawberries, if you don't have fresh strawberries. Then, add the remaining ingredients to the saucepan and stir to combine. Cook the mixture over medium-low heat until the sugar dissolves, about 5 minutes. Remove the pan from the heat, stir in the butter and vanilla and cook for an additional 5 to 10 minutes, or until thickened and bubbly. Pour the sauce into jars and store in an airtight container for up to 3 months.