Preheat the oven to 300°F (150°C) and line two baking sheets with parchment paper. In a mixing bowl, whip egg whites until foamy, then incorporate granulated sugar and cream of tartar gradually until stiff peaks form.

Sift together the almond flour and powdered sugar in a separate bowl to eliminate clumps, ensuring a smooth mixture.

Gently fold the dry ingredients into the meringue using a silicone spatula until the batter reaches a "lava-like" consistency.

Transfer the batter into a piping bag and pipe circles onto the prepared sheets. Tap the baking sheets to release air bubbles and let rest for 30-60 minutes.

Bake the macarons for 15-18 minutes, rotating halfway through. They should be firm to the touch.

To prepare the ganache, heat heavy cream until simmering, pour over chopped dark chocolate, and stir until smooth. Add butter for a glossy finish.

Pair similar-sized macaron shells. Spread raspberry jam on one and ganache on the other, then sandwich them together.