Preheat the oven to 170°C.
Rub the butter, sugar, vanilla seeds, and flour together in a bowl using your fingertips.
Form a dough, knead on a floured surface until smooth, wrap in film, and chill for 15 minutes.
Roll the chilled dough on a floured surface to a thickness of 6mm.
Cut 7.5cm discs from the dough using a cutter.
Cut small 1.5cm heart shapes out of the center of half the discs.
Place discs on a greased tray and bake for 12-15 minutes until crisp and golden.
Cool on a wire rack.
Spread a teaspoon of clotted cream and a dollop of jam onto whole biscuits.
Top with heart-cut biscuits and squeeze gently together.