Mix flour, salt, butter, one egg, and 40ml water into a bowl until smooth.
Divide the dough in half and knead poppy seeds into one portion.
Knead parmesan and sun-dried tomato paste into the second half of the dough.
Roll out both dough pieces to a thickness of 3mm.
Place dough on a tray, cover, and refrigerate for 30 minutes.
Preheat the oven to 200°C and flour two large baking trays.
Cut 18 rounds from each dough portion using a 7cm round cutter.
Brush biscuits with beaten egg and top the tomato-parmesan rounds with sesame seeds.
Bake for 10-15 minutes until golden-brown and cool on a wire rack.