Preheat oven to 350 degrees and line a cookie sheet with parchment paper; set aside. In a large bowl, blend together the butter and SunButter using an electric hand mixer. Add in the egg and dry cookie mix, then blend until a dough forms.
Shape dough into tablespoon sized balls and place at least 1" apart on prepared pan. Use a fork to slightly flatten cookies, making a criss-cross shape. Bake 10-12 minutes, until the edges become golden. Remove from oven and cool cookies completely on a wire cooling rack.
Place white chocolate in a microwave safe bowl. Heat in 30 second increments until melted and smooth, stirring after each time. Drizzle white chocolate over cooled cookies, then sprinkle with colored sugar. Enjoy immediately!
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