Mix the almonds with half of the powdered sugar in a food processor. Grind the mixture and sift it through a sieve to remove any large pieces. Set aside.

Weigh the egg whites precisely and whip them with a pinch of salt until stiff peaks form. While still mixing, gradually add the remaining powdered sugar. Continue to mix until smooth and shiny. Divide the mixture into 3 equal parts and place each in a separate bowl.

To the first bowl, add ⅔ of a teaspoon of cocoa powder. To the second, add ⅔ of a teaspoon of instant coffee and remaining ⅓ teaspoon cocoa powder. To the third, add ⅓ teaspoon instant coffee. Mix each briefly, just until a uniform color is achieved.

Gently fold one-third of the almond and powdered sugar mixture into each of the three flavored mixtures using a silicone spatula. Mix each of them only until the ingredients are combined and you have a smooth batter for each flavor.

Line a baking sheet with parchment paper or use a silicone baking mat. Transfer the batter to a piping bag with a round tip, one flavor at a time. Hold the pastry bag vertically and pipe the batter to create macarons with a diameter of approximately 1⅕ inches (the batter will spread a bit). Repeat until you use all three batters.

Tap the baking sheet with the piped macarons on the countertop several times to remove any air bubbles. Let the macarons sit for an hour to develop a dry surface. They are ready for baking when the surface no longer sticks to your finger when gently touched.

Preheat the oven to 300°F convection mode. Bake the macarons for 15 minutes. Remove from the oven and cool completely on a wire rack. Once cooled, the bottom of the macarons should be dry, and the center slightly moist. Carefully peel them off the mat (or parchment paper).

In the meantime, prepare the chocolate ganache. In a saucepan, heat the heavy cream almost to a boil, then remove from the heat. Add the chopped dark chocolate and let it sit for 2 minutes. Stir the mixture until you have a smooth chocolate sauce. Allow the ganache to cool and thicken slightly. Once it has reached the desired consistency, transfer the ganache to a pastry bag fitted with a round tip.

Fill the cooled macarons with the prepared filling. To fill the macarons, spread a layer of ganache on one macaron shell and then sandwich it with another shell of the same flavor to create a sandwich. Refrigerate the macarons 1-2 hours until the ganache sets. Enjoy.