Magical Royal Icing for Sugar Cookie Decorating
1) Sift 2.25 pounds (that's 36 ounces or 1021 grams) of powdered sugar into a large bowl. Set aside.
2) Combine warm water and meringue powder in small bowl, and whisk until dissolved (about 45 seconds).
3/4 cup (that's 6 ounces) of warm water
5 Tablespoons of Meringue Powder
3) Then add the cream of tarter to your water/meringue mixture and whisk until dissolved (about 45 seconds).
1 teaspoon of Cream of Tarter
4) Transfer this mixture (water/meringue/cream of tarter) into your large electric mixer bowl and slowly add the pre-sifted powdered sugar on your mixer's SLOW or STIR setting.
2 1/4 pounds (36 ounces or 1021 grams) of SIFTED powdered sugar.
5) Using a clean, grease free spatula ensure the sides are scraped down and all sugar is incorporated and then continue mixing at SLOW or STIR setting, for 10 to 12 minutes.
That's it! All that's left to do is ensure it's the right consistency for piping and flooding. You do that by adding water (I use a spray bottle so I don't thin it too much). This recipe will produce a consistency much like the spackle one uses to patch holes in walls. For piping, thin it to a consistency similar to toothpaste. If it breaks when you pipe, it's too thick. If it doesn't stay in place or doesn't hold the rounded shape, it's to thin (just add more spackle). Tip: add color first and then thin it (otherwise, the color may spoil your perfect consistency and then you'll have to add spackle and then your color's not perfect anymore). For flooding, you want to add enough water that it resembles honey or shampoo. That way it'll relax and flatten perfectly. Do this thinning (and coloring) as you need it, leaving the master batch (spackle) in an airtight container. For flooding, I like my icing thin enough that when you run a knife through the top of the frosting in my mixing bowl, it takes between 5 and 10 seconds for the "line" to completely disappear (but note that everyone "counts" at a different speed. For some, this may be 10 to 15 seconds). Five seconds will be very runny and inappropriate for anything but the tiniest of decorating tips, and anything over 10 seconds will be a fight to work with and won't have that beautiful glossy appearance when the cookie is finished.
TIP: This frosting dries quickly. That means your batch will be ruined (never stir in a crunchy top thinking you can save the batch of frosting -- the bits will block your decorating tip and ruin your designs) if it dries out even a bit. So -- keep your frosting in an airtight container or keep a damp kitchen towel over your bowls at all times. Also keep your tips (on filled bags) in a little bit of damp paper towel to prevent drying.
That's it. Have fun!