1. Make the Macaron Shells

1. Line two baking sheets with parchment paper or silicone mats.
2. In a bowl, sift together almond flour, ground pistachios, and powdered sugar. Discard large pieces.
3. In a separate large bowl, beat egg whites until foamy, then gradually add granulated sugar, whisking until stiff peaks form.
4. Fold in vanilla extract and food coloring, if using.
5. Gently fold the dry ingredients into the egg whites using a spatula until the batter flows in thick ribbons (about 50 strokes).
6. Transfer batter into a piping bag fitted with a round tip and pipe 1-inch circles onto the baking sheets.
7. Tap the trays on the counter to remove air bubbles. Let them sit at room temperature for 30-60 minutes until a skin forms.

2. Bake the Macaron Shells

1. Preheat oven to 300°F (150°C).
2. Bake for 12-15 minutes, until firm and slightly golden at the edges.
3. Let cool completely before filling.

3. Make the Raspberry Buttercream

1. In a bowl, beat butter until creamy.
2. Gradually add powdered sugar and beat until smooth.
3. Mix in raspberry jam, vanilla, and salt, beating until fluffy.

4. Assemble the Macarons

1. Pipe raspberry buttercream onto half of the shells.
2. Top with remaining shells, gently pressing to form sandwiches.
3. Chill for 24 hours for best texture.