Preheat your oven to 300°F (150°C). Whip room temperature egg whites until soft peaks form, about 3-4 minutes. Gradually add granulated sugar until stiff peaks form and meringue is glossy. Fold in sifted almond flour and confectioners' sugar until just combined; the batter should flow like lava.

Transfer the macaron batter to a piping bag fitted with a round tip. Pipe small rounds on a parchment-lined baking sheet, about 1.5 inches in diameter. Tap the sheet to eliminate air bubbles. Let rest for 1-2 hours until a skin forms.

Bake the macarons for 15-17 minutes until they develop feet and feel firm. Rotate the baking sheet halfway through for even baking.

While shells cool, prepare the buttercream. Beat softened unsalted butter until creamy, gradually add the confectioners’ sugar, then add the vanilla extract and whole milk until smooth and fluffy.

Once the shells are cool, pipe a dollop of buttercream on one shell, top with chopped strawberries, and sandwich with another shell. Repeat until all macarons are filled.