Separate the yolks and whites of 4 or 5 eggs and weigh the whites to exactly 4 oz. (115 g).
Divide the whites evenly between two bowls. In a large bowl, sift together the almond flour and confectioners' sugar.
Add one of the bowls of egg whites to the almond mixture along with flavoring.
Mix vigorously with a silicone spatula.
In the bowl of a standing mixer fitted with the whisk attachment, begin beating the remaining egg whites until soft peaks form.
Add the sugar, food coloring, and 3 tbsp (45 mL) water to a small saucepan. Heat over high heat to 250°F/121°C (if you do not have a candy thermometer, drop a small quantity of the hot syrup into a bowl of cold water. It should form a ball and feel soft when pinched between your fingers). When the syrup reaches 250°F/121°C, pour it in a steady stream down the inside edge of the bowl with the mixer on medium speed.
Adjust the color, if necessary, by adding more coloring. Continue beating for several minutes on low speed until the whites are stiff and glossy.
Incorporate a small amount of the meringue into the almond flour mixture to lighten it.
Gently incorporate the remaining meringue while folding the batter to deflate it.
Pipe the shells. Line a baking sheet with parchment paper. Scrape the batter into a pastry bag fitted with 1/3-in (10-mm) plain pastry tube.
For individual macarons, pipe shells 2 1/4 in (6 cm) to 2 3/4 in (7 cm) in diameter. Pipe the macaron batter in a spiral, starting at the center, without any gaps in between the lines.
Let the piped shells sit at room temperature for 1 hour to allow a skin to form (the batter should not feel sticky when lightly touched with your finger).
Meanwhile, preheat the oven to 250°F/125°C. Bake for 16 minutes (the shells should not begin to brown).
Raspberry-lime filling and decoration
Make the raspberry-lime filling. In a large bowl, combine the preserves, almond flour, and zest.
Make the decoration. In a heatproof bowl set over a pot of simmering water, melt the chocolate over very low heat without stirring (or place in a microwave-safe bowl and microwave for 1 minute). Stir briefly, then add the food color and stir to combine well. Pour the colored chocolate into a small paper cone, then lightly stripe the tops of the macaron shells with it in a zigzag pattern.
Scrape the filling into a pastry bag fitted with a 1/3-in pastry tube. Turn half of the shells over with the flat sides up onto a piece of parchment paper and fill them with the filling. Cover them with anther shell, pressing down gently.
Refrigerate for at least 24 hours in an airtight container before serving.