

Use immediately as a thick frosting or to make chunky decorations, like the buttons on a gingerbread man or little rosettes on a cake color, if desired, according to instructions in step 3. Increase speed to medium and beat until thick and frosting-like, about 20 seconds or until the mixing bowl feels cool to the touch. Beat in egg whites with an electric mixer until mixture is thick enough to hold its shape, about 5 minutes. Transfer to stand mixer fitted with a paddle attachment, add remaining 2 ounces powdered sugar (1/2 cup 60g), and mix at low speed to combine. Sift together confectioners' sugar and cream of tartar in a large bowl. Stir with a flexible spatula to form a smooth paste, then set over a gently simmering water bath in a 3-quart saucier and stir until paste is hot to the touch, or about 150☏ (66☌) on an instant-read thermometer. The meringue powder helps thicken and harden the icing more quickly than just time and dry air temperature. If the icing that drips off disappears in the bowl of icing in 5-10 seconds, then it’s the right consistency for flooding. Lift up the paddle and check the consistency of the icing by letting the icing drip off the paddle and back into the bowl.

Whip on medium speed until the icing holds stiff peaks. If you make royal icing with just powdered sugar and water, then it can take up to 24 hours for the icing to dry and harden. Mix with the paddle attachment on medium/low speed for 2 minutes. As the mixture begins to come together, add in orange juice. To Make the Icing: Measure 16 ounces powdered sugar (4 cups 450g) and place in the bowl of a stand mixer, then add egg whites, rum, vanilla, salt, and cream of tartar. With a standing mixer with a whisk attachment (or a hand mixer), whisk powdered sugar, meringue powder, water (starting with 6 Tbsp of water), and vanilla extract.
