Salted Caramel Macaron

Sift the powdered sugar with the almond flour.

Mix 110 g of egg whites with the food coloring and coffee extract.

Pour over the almond-sugar mixture without stirring.

Boil the mineral water and granulated sugar to 118 °C (244 °F).

When the syrup reaches 115 °C (239 °F), begin whipping the second 110 g of egg whites to soft peaks.

Pour the syrup over the whipped egg whites and continue whipping. Let cool to 50 °C (122 °F).

Fold gently into the almond-sugar-egg white mixture.

Transfer the batter to a piping bag fitted with a plain tip (size 11).

Pipe rounds about 3.5 cm in diameter on parchment-lined baking sheets, spacing them 2 cm apart.

Tap the trays to slightly spread the batter. Let the shells dry at room temperature for at least 30 minutes.

Preheat the oven to 180 °C (356 °F) with a fan setting.

Bake for 12 minutes, opening the oven door twice briefly to release moisture.

Slide the parchment with shells onto the counter to cool.

Bring the heavy cream to a boil.

In a heavy-bottomed saucepan, melt about 50 g of sugar over medium heat.

Continue adding the sugar in increments, allowing each addition to melt before adding the next.

Cook the caramel until it reaches a deep amber color.

Off the heat, stir in the salted butter.

Gradually add the hot cream in two additions.

Return the pan to the heat and cook to 108 °C (226 °F).

Blend with an immersion blender and chill in the refrigerator.

Whip the butter in a stand mixer fitted with a whisk for 10 minutes until fluffy.

Incorporate the cooled caramel and mix until smooth.

Transfer to a piping bag fitted with a plain tip (size 11).

Turn half of the shells upside down.

Pipe a dollop of salted caramel cream onto the flat side.

Top with a second shell and press gently to sandwich.

Refrigerate the macarons for 24 hours.

Bring to room temperature 2 hours before serving.