Ingredients
Equipment
Method
- Cream butter and sugar: In the bowl of a stand mixer, beat the room-temperature butter and granulated sugar together on medium-high speed for 3-4 minutes until light, fluffy, and pale.
- Add wet ingredients: Beat in the egg, the scraped seeds from the vanilla bean, and the vanilla extract until fully combined.
- Combine dry ingredients: In a separate bowl, whisk together the flour, baking powder, and salt.
- Form dough: Gradually add the dry ingredients to the butter mixture, mixing on low speed just until the dough comes together with no dry streaks remaining.
- Chill dough: Divide the dough in half, shape each half into a disc, wrap tightly in plastic wrap, and refrigerate for at least 2 hours (or up to 2 days).
- Preheat oven: Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.
- Roll and cut: On a lightly floured surface, roll one disc of chilled dough to about ¼-inch thickness. Dip a shamrock cookie cutter in flour and cut out shapes. Transfer shapes to the prepared baking sheets, spacing them about 1 inch apart. Re-roll scraps and repeat. Keep the second disc chilled until ready to use.
- Bake: Bake cookies for 8-10 minutes, or until the edges are just barely beginning to turn golden and the centers look set.
- Cool: Let cookies cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely before decorating.
- Make royal icing: In a clean mixer bowl, combine the sifted powdered sugar and meringue powder. With the mixer on low, slowly add 5 tablespoons of warm water. Increase speed to medium-high and beat for 2-3 minutes until thick, glossy, and holding stiff peaks (outline consistency).
- Thin icing for flooding: Transfer about one-third of the stiff icing to a separate bowl. Add warm water drop by drop, stirring, until it reaches a thick syrup consistency that smooths out within 10-15 seconds when drizzled (flood consistency).
- Color icing: Tint both the outline and flood consistencies of icing with green gel food coloring.
- Outline cookies: Using a piping bag fitted with a small round tip, pipe an outline around the edge of each completely cooled cookie with the stiffer icing.
- Flood cookies: Immediately fill (flood) the outlined area with the thinner icing. Use a toothpick or scribe tool to guide the icing into corners and pop any air bubbles.
- Add details (optional): Use additional icing in a darker green or white to pipe stems, dots, or other decorative details.
- Dry completely: Allow the decorated cookies to dry, undisturbed, for at least 6 hours or overnight until the icing is fully hard and set.
Notes
For best results, ensure all ingredients (butter, egg) are at room temperature before starting. If the dough becomes sticky while rolling, return it to the refrigerator for 10 minutes. If the flood icing becomes too runny, fix it by adding a little more sifted powdered sugar. Store completely dried cookies in an airtight container at room temperature for up to 5 days. For longer storage, undecorated baked cookies can be frozen for up to 3 months.