Combine the refrigerated dough with the flour using a wooden spoon and your hands to knead it until smooth.
Use a rolling pin to roll the dough out to ¼-inch thickness. Use cookie cutters to cut out heart shapes, and use a ruler to cut ½” x 3” rectangles.
Bake at 350°F/ 177°C for 8 minutes or until the edges start to brown. Allow cookies to cool completely before decorating.
To Make Icing and Decorate
In a stand mixer fitted with the paddle attachment, combine powdered sugar and meringue powder.
Add in 8 tablespoons of water, and beat for 1 minute on low speed.
Continue to add water, one tablespoon at a time until the icing slowly drizzles from the paddle when lifted.
Separate icing into smaller bowls and color as desired using gel food coloring. Add royal icing to squeeze bottles.
Working on a few cookies at a time, use the bottle to outline each with icing, then quickly fill in the outline to create the background of your design.
While still wet, decorate using sprinkles, or a contrasting color of icing.
Allow cookies with royal icing to harden for at least 4 hours before adding any writing with an edible marker, or additional royal icing details.
Notes
For these wet on wet decorated cookies, your icing should be at a medium consistency. If you take your whisk or a spoon and drizzle a line of icing into the bowl, it should take 13-15 seconds to settle into the icing and disappear.
Decorate quickly so that the icing doesn't harden before you're finished. This will allow your cookies to be smooth and seamless.
Use a toothpick to pop any air bubbles and to get icing into corners and bare spots.
If your icing is too thick, add drops of water until it is the right consistency.
If the icing is too thin, you can mix in additional powdered sugar.
Store decorated cookies at room temperature in an airtight container for up to 5 days, or in the freezer for up to three months.
Feel free to use your favorite sugar cookie cut-out recipe in place of the easy shortcut recipe here.