Preheat the oven to 300°F (150°C). Line a baking sheet with parchment paper.
In a bowl, sift together the almond flour and powdered sugar to remove lumps. Set aside.
In a separate bowl, whip the egg whites until frothy. Gradually add the granulated sugar, continue whipping until stiff peaks form.
Gently fold the almond flour mixture into the whipped egg whites until combined. If desired, add food coloring to achieve a pastel hue.
Transfer the mixture to a piping bag. Pipe small circles (about 1.5 inches in diameter) onto the prepared baking sheet, leaving space between each.
Tap the baking sheet firmly on the counter to release any air bubbles. Let the macarons sit at room temperature for 30 minutes, until a skin forms.
Bake the macarons for 15 minutes until they rise and form feet. Remove from the oven and allow to cool completely on the baking sheet.
While the macarons cool, prepare the berry filling. In a saucepan, heat the mixed berries over medium heat until they soften. Mash them lightly with a fork.
Remove from heat and let cool. Once cooled, fold in the whipped cream, powdered sugar, and vanilla extract until smooth.
Once the macarons have cooled, pair them up and spoon a dollop of berry filling on half of the shells. Top with the other macaron shells to create sandwiches.