Trim the brown crust off the top, bottom and sides of the angel food cake using a serrated knife. Thinly slice the cake.
Whisk 1/2 cup heavy cream and 1/4 cup malted milk powder in a small bowl until the powder is mostly dissolved; let sit 5 minutes, then whisk again until the powder is completely dissolved and the mixture is slightly thickened. Lightly coat the bottom and sides of a 10-inch tube pan with cooking spray. Press about half of the cake slices into the bottom of the pan and slightly up the sides in a single layer, trimming as needed. Drizzle half of the malted cream over the cake slices.
Scoop half of the ice cream into the pan and spread with an offset spatula to make an even layer. Press some of the remaining cake slices on top of the ice cream to make an even layer, trimming the slices as needed. Drizzle with the remaining malted cream. Repeat with the remaining ice cream and cake slices. Cover with plastic wrap and freeze until firm, at least 4 hours and up to 5 days.
Loosen the edges of the cake with an offset spatula, then invert onto a platter. Beat the remaining 1 cup heavy cream and 2 tablespoons malted milk powder with a mixer until stiff peaks form. Spread over the top and sides of the cake and top with sprinkles.