Preheat the oven to 350° and line 2-3 cookie sheets with parchment paper.: The warm, slightly sweet scent that fills the kitchen as the oven comes to temperature signals readiness; you want an even oven heat so the cookie edges set without darkening. Use parchment to prevent sticking and to keep bottoms pale. Common mistake to avoid is overcrowding the trays, which leads to uneven baking and merging cookies.
In a medium bowl whisk together the flour, salt, and baking powder. Set aside.: After whisking, the dry mixture should look uniform and powdery, with no clumps. This ensures even rise and a consistent texture. If you skip whisking, you risk pockets of leavening or salt that create off textures and flavors in individual cookies.
In another medium bowl, beat together the butter and sugar for 2-3 minutes until light and fluffy. Add the egg yolks, sour cream, and extracts and mix until just combined.: As you beat the Unsalted Butter and Granulated Sugar , you should see the mix turn pale and airy, a visual cue that air has incorporated for a tender bite. Adding Egg Yolks and Sour Cream will create a creamy, slightly glossy batter texture. Avoid overmixing at this stage, which can lead to tough cookies due to excess gluten development.
Add the dry ingredients to the wet and mix until just barely combined.: Once combined, the dough will come together without looking overly wet; streaks of flour should disappear with gentle folding. The right texture feels pliable and slightly tacky but not sticky. Overworking here often causes the dough to become dense, so stop mixing as soon as the ingredients are integrated.
This recipe does not require any chilling time, so you’re ready to roll out your cookies! Split the dough into 2-3 pieces and roll them one at a time on a lightly floured surface until they are 1/4 inch thick. Use your favorite Christmas tree cookie cutters (or alternative shapes!) to cut out your cookies. Press the scraps together and set them aside to rest for about 5 minutes. Reroll the scraps and cut more cookies until all the dough has been used.: The dough should roll smoothly without cracking; a lightly floured surface prevents sticking but avoid excess flour which dries the cookie edges. Resting scraps briefly lets the dough relax so rerolled cookies hold shape. A trap is rolling too thin, which results in crisp, fragile cookies, or too thick, which can leave underbaked centers.
Place the cookies on the parchment-lined cookie sheets leaving 1 1/2 inches between them. Bake for 6-8 minutes, rotating the pan at 4 minutes. I find this gives the cookies a nice, even bake. The edges will be just set and the cookies will be very light in color and should have very minimal coloring underneath them.: As the cookies bake you will notice they remain very pale, and the edges should look just set without browning; that pale, barely colored surface indicates a tender interior. Rotating at the halfway point evens heat exposure. Common error is overbaking until golden brown, which yields a cookie that is too crisp rather than soft and tender.
Let the cookies cool on the pan for 2 minutes for the shape to set before transferring them to a cooling rack. Frost, once they are cooled then store in an airtight container until you are ready to frost them.: The brief rest on the pan allows the cookie structure to firm up so corners stay crisp. When moved to a rack, cookies will feel slightly firm but still warm to the touch. If you frost while even slightly warm, the icing will soften and run, so patience is essential.
Using an electric mixer with the whisk attachment, mix the powdered sugar and meringue powder together on low.: The dry mix should be bright and lump free before you add water, which prevents gritty icing. Mixing on low minimizes sugar dust clouds and ensures the Meringue Powder is evenly distributed. A typical issue is adding water too quickly, causing the icing to become too loose to hold shape.
Add 8 tablespoons of water and mix together on high speed for about 2 minutes. The icing should be pretty stiff. Add additional water 1 tablespoon at a time until the icing is about the consistency of soft-serve ice cream and forms soft peaks. Reserve 1 cup of frosting and cover tightly with plastic wrap.: At high speed the icing will turn glossy and thick; when you lift the whisk it should form soft peaks like soft serve . Reserving thicker icing gives you piping control for outlines. A frequent mistake is over thinning the reserved piping icing, which then will not hold crisp edges.
With the remaining icing, add additional water 1-2 teaspoons at a time until when the whisk is raised the icing drips back into the bowl and the lines of icing take about 10 seconds to melt back into the icing. This is the thin icing that will be used to fill, or flood, your cookies. Separate into small bowls and tint the icing with your chosen colors. Cover each bowl tightly with plastic wrap when not being used. This icing will dry very quickly.: The flood consistency should be fluid but not watery; when dripped from a spoon it should settle smoothly within ten seconds. Tinting with Gel Food Coloring keeps the icing vibrant without changing consistency. Avoid adding too much water initially, which creates runny icing that bleeds under outlines.
Separate the reserved thicker icing into bowls and tint the bowls the colors you want to make your eggs. This will be the frosting that is piped around the outside of the cookie to hold the thin icing in the center. Be sure to cover the bowls until ready to use. When ready to ice the cookies, pipe the thicker outline and then flood the center with the thin icing and add the details with thin icing.: The thicker piping icing should hold peaks and create clean edges that contain the flood. Piping an outline first produces that crisp bordered look, and the contrast between the firm edge and glossy fill is satisfying to the eye. A common pitfall is not covering bowls which leads to skin forming on the icing, so keep them wrapped until you use them.
