Preparation Steps

• In a medium bowl, whisk together the flour, baking powder and salt until evenly combined. Set this dry mix aside.
• In the bowl of a stand mixer fitted with the paddle (or using a large mixing bowl and an electric hand mixer), beat the softened butter and granulated sugar on medium-high for 3–4 minutes until the mixture is pale and fluffy. Scrape down the sides once or twice.
• Reduce the mixer speed to low and add the eggs one at a time, mixing until each is incorporated. Add the vanilla extract and orange zest and mix just until smooth.
• With the mixer on low, add the dry ingredients in two additions, mixing only until the dough comes together. Avoid overmixing — stop as soon as there are no dry streaks. Gather the dough into a ball and divide it into two equal portions.
• Place each portion in a separate bowl. Add the orange gel to one portion and the black gel to the other. Knead each piece (wear gloves or use a sturdy spatula) until the color is even. If a portion feels too sticky, fold in up to 1 tablespoon additional flour.
• Flatten each colored dough between two sheets of parchment into roughly 9 x 12 inch rectangles about 1/4 inch thick. Refrigerate both rectangles for 30 minutes so they are firm but still pliable.
• Remove parchment and stack the orange rectangle on top of the black. Starting from a short side, roll the stacked rectangles tightly into a log about 2 inches in diameter. Wrap the log tightly in plastic wrap and chill for at least 1 hour (longer is fine) until very firm.
• About 15 minutes before you plan to bake, preheat the oven to 350°F and line baking sheets with parchment paper.
• Unwrap the chilled log and slice into rounds 1/4 to 1/2 inch thick. Arrange the slices on the prepared baking sheets about 1 inch apart.
• Bake one sheet at a time for 10–12 minutes, until the edges are set and the centers look just cooked. Rotate the sheet halfway through for even browning if needed.
• Let cookies cool on the baking sheet for 2–3 minutes, then transfer to a wire rack to cool completely. Store in an airtight container at room temperature for up to 5 days or freeze for longer storage.