Finely chop white chocolate and place in a heatproof bowl. Heat heavy cream in a saucepan until it simmers, pour over chocolate, stir until smooth, and mix in crushed Oreos. Cool in fridge for an hour.

Preheat oven to 145°C (290°F). Sift together almond flour, powdered sugar, and crushed Oreos in a mixing bowl.

In a clean bowl, whip egg whites until foamy, gradually adding granulated sugar until stiff peaks form.

Gently fold almond mixture into egg whites without deflating. The batter should flow in a thick ribbon.

Transfer the batter into a piping bag and pipe mounds onto a lined baking sheet. Tap to release air bubbles.

Let the batter rest at room temperature for 45 minutes until a skin forms.

Bake for 14-15 minutes until the macarons slightly detach from the parchment.

Once cool, pipe ganache onto one macaron and sandwich with another. Refrigerate for 24 hours before serving.