Meanwhile, add strawberries and butter to a saucepan and set on medium heat. Cook, stirring often until strawberries are soft. Add strawberries, strawberry jam and white chocolate chips (the heat from the strawberries will melt the white chocolate) to a blender and blend until completely smooth. Next, add 2 cups powdered sugar and blend again until smooth. If needed, add remaining 1/2 cup of powdered sugar to thicken the glaze.