Prep: Soften butter until easy to press.
Whip: Add sugar and salt. Whip butter until pale and fluffy. (Tip: Place bowl over warm water 32°C if kitchen is cold).
Milk: Add milk in 2 batches, whisking well after each until absorbed.
Combine: Sift in cake flour and almond flour. Fold gently with a spatula until no dry powder remains.
Pipe: Transfer to piping bag with open star tip. Pipe onto baking tray.
Chill: Refrigerate tray for 20 minutes to set shape.
Bake: Bake at 160°C (320°F) for 20-25 minutes. Cool completely.