Prep the oven and pan: Preheat your oven to 225°F (110°C). Line two baking sheets with parchment paper. Make sure your mixing bowl and whisk are squeaky clean and dry. Any grease will prevent the meringue from whipping properly.
Warm the sugar (optional but helpful): Spread the sugar on a baking sheet and warm it in the oven for about 5 minutes. Warm sugar dissolves faster, leading to a smoother, glossier meringue. Don’t let it melt or brown.
Start the meringue: Add the egg whites, cream of tartar, and salt to a stand mixer bowl. Whip on medium speed until soft peaks form and the mixture looks foamy and opaque, about 2–3 minutes.
Add sugar gradually: Increase to medium-high speed and slowly sprinkle in the warm sugar, 1–2 tablespoons at a time. Take your time. This helps the sugar dissolve and prevents weeping later.
Whip to stiff, glossy peaks: Continue beating until the meringue is thick, shiny, and holds stiff peaks that stand straight up. Rub a tiny bit between your fingers; it should feel mostly smooth, not gritty. This can take 5–8 minutes total.
Add flavor: Beat in the vanilla just until blended. Avoid overmixing at this stage to keep the meringue stable.
Prepare the colored swirls: Turn a piping bag inside out halfway over your hand or a tall glass. Use a clean food-safe brush or toothpick to paint thin vertical lines of gel food coloring inside the bag—2 to 4 stripes, spaced evenly. Less is more for a soft pastel effect.
Fill the bag: Spoon the meringue into the bag carefully, trying not to smear the colors too much. Twist the top to seal and push the meringue down to the tip.
Pipe the kisses: Hold the bag straight up, about half an inch above the parchment. Squeeze to form a small mound (about 1 to 1.5 inches wide), then stop pressure and flick your wrist up to create a neat point. Leave a little space between each one for airflow.
Bake low and slow: Place both trays in the oven and bake for 60–75 minutes, rotating trays halfway through. The kisses should feel dry to the touch and lift cleanly from the parchment. They should not brown.
Dry in the oven: Turn off the oven and leave the meringues inside with the door closed for another 30–60 minutes. This gradual cool-down helps prevent cracks and tackiness, especially in humid climates.
Cool completely: Remove and let them cool fully on the trays before transferring. They should be crisp on the outside and slightly chewy in the center.
