Step 1: Sift the almond flour and 130g of powdered sugar together into a large bowl. Discard any large almond pieces to ensure smooth robins egg oreo macarons.
Step 2: In a clean glass bowl, whisk the egg whites on medium speed until frothy. Gradually add the granulated sugar while increasing the speed to medium-high.
Step 3: Continue whisking until stiff, glossy peaks form. Add a small amount of blue gel food coloring and whisk just until the color is even.
Step 4: Gently fold the dry ingredients into the meringue using a silicone spatula. Perform the ‘macaronage’ until the batter falls off the spatula in a continuous ribbon, like slow-moving lava.
Step 5: Transfer the batter to a piping bag with a round tip and pipe 1.5-inch circles onto a baking sheet lined with parchment paper or a silicone mat.
Step 6: Tap the tray hard 4-5 times on the counter to remove air bubbles. Let the shells rest for 30-60 minutes until a dry skin forms on top.
Step 7: Preheat your oven to 300°F (150°C). Bake the shells for 14-16 minutes. Allow them to cool completely on the tray before removing.
Step 8: To speckle the robins egg oreo macarons, dip a clean brush into the cocoa-vanilla mixture and flick the bristles over the cooled shells.
Step 9: Prepare the filling by beating the butter until creamy, then adding powdered sugar, crushed Oreos, vanilla, and cream. Mix until smooth and fluffy.
Step 10: Match shells of similar size, pipe a dollop of Oreo filling onto one shell, and sandwich with another. Refrigerate for 24 hours for best flavor.