Preheat oven to 350°F. Line a large baking sheet with parchment paper.
Mix together flour, malted milk powder, baking powder, and salt.
In a mixing bowl, using an electric mixer, beat together softened butter, sugar and gelatin until creamy, then beat in egg, scraping side of bowl often. Stir in vanilla, then stir in flour mixture to form a dough.
Turn dough out onto baking sheet. Dampen hands and form into a log. The log should be around an inch high and a little less than 3 inches wide.
Bake log for 25 minutes or until slightly firm to the touch.
Reduce oven heat to 300 degrees F.
Carefully transfer biscotti log (just lift the parchment) to a cutting board, and cut slightly on the diagonal to make ¾ inch slices. For this biscotti, a non-serrated knife works best, and use a one cut motion rather than a sawing motion.
Carefully transfer biscotti back to baking sheet and lay them on their sides.
Bake for about 25 to 30 minutes, flipping halfway through. Alternatively, you can just stand them on their bottoms and avoid flipping.
Let cool completely. When cool, dip in your favorite brand of white coating (or white chocolate) and decorate with rainbow sprinkles.