- 1 cup plus 2 tablespoons sugar
- 5 large egg whites or pasteurized egg whites
- 4 sticks unsalted butter, room temperature, cut into tablespoons
- 1 teaspoon pure vanilla extract
- Gel-paste food coloring in Red Red (<a href="http://nycake.com" target="_blank">nycake.com</a>)
- Poppy seeds, for sprinkling
- Heat sugar and egg whites in the heatproof bowl of a mixer set over a pan of simmering water, whisking constantly, until sugar dissolves and mixture reaches 140 degrees on an instant-read thermometer, about 2 minutes.
- Whisk with mixer on medium-high speed until fluffy and cooled, about 10 minutes. Whisk until stiff, glossy peaks form, about 2 minutes more.
- Reduce speed to medium-low, and add butter, 1 tablespoon at a time, beating well after each addition. Beat in vanilla.
- Switch to the paddle attachment, and raise speed to medium. Beat buttercream until smooth, 1 to 2 minutes.
- Pipe the poppies: Transfer one-quarter of the buttercream to a bowl (reserve remainder for frosting cupcakes), and tint with food coloring until you reach desired color for poppies. Transfer to a pastry bag fitted with a large petal tip. Cut out twenty 2-by-3-inch rectangles of parchment. Adhere 1 parchment rectangle to a flower nail with a dab of buttercream. Holding the piping bag at a 45-degree angle, pipe 1 petal. Pipe a second petal, overlapping the first by 1/2 to 3/4 inch. Making a tighter turn with the nail, overlap the second petal to pipe a third.
- Sprinkle poppy seeds in the centers of flowers to create the look of stamens. Gently remove parchment from nail, and transfer to a baking sheet. Repeat with remaining parchment and tinted buttercream. Refrigerate poppies for at least 2 hours.
- Gently remove poppies from parchment using an offset spatula. Place 1 on top of each cupcake.
Buttercream can be refrigerated for up to 1 week or frozen for up to 1 month. Bring to room temperature before using, and beat on low speed until smooth, about 3 minutes. Buttercream poppies can be refrigerated for up to 2 days.