Make the buns: In a mixing bowl, combine warm milk, melted butter, sugar, and yeast. Let sit until foamy. Add flour, cardamom, and salt, stirring into a dough. Knead for 5–6 minutes until smooth. Cover and let rise for 1 hour.
Shape and bake: Divide dough into 4–6 equal pieces and shape into balls. Place on a parchment-lined baking tray, cover, and let rise 30 minutes. Bake at 375°F (190°C) for 12–15 minutes until golden. Cool completely.
Prepare filling: Mix almond flour, powdered sugar, and milk to create a thick paste.
Assemble: Slice a small “lid” off each bun. Hollow out some crumbs from inside. Mix crumbs into the almond paste for extra texture, then spoon the mixture back into each bun.
Whip cream: Beat cream with powdered sugar and vanilla until soft peaks form. Pipe or spoon onto buns. Replace the bun lids and dust with powdered sugar.