Peanut Butter Sandwich Cookies

Steps

• Shells: Cream the butter, peanut butter, and both sugars until combined, then beat in the egg and vanilla.
• Shells: Mix in the flour, baking soda, and salt just until the dough comes together.
• Shells: Divide in two, flatten into discs, wrap, and chill until firm.
  ⏱ Start 45 min timer
• Shells: Roll each disc to an even 1/8 inch between two sheets of parchment and cut 2-inch rounds. Space on a lined sheet.

  Tip: Even thickness is everything for sandwich shells — mismatched pairs won't sit flat and will crack when pressed together.

• Shells: Bake at 175°C (350°F) until evenly golden and dry right through, then cool completely on a rack.
  ⏱ Start 10 min timer
• Filling: Beat the filling peanut butter and butter until smooth, then add the icing sugar, milk, and salt and beat until stiff but spreadable.

  Tip: Aim for a filling that holds a peak but gives under a knife. Too firm and biting the sandwich will crack the top shell.

• Assemble: Match the shells into similar-sized pairs, pipe or spread filling on the flat side of one, and press gently until the filling just reaches the edge.