Step 1
Preheat the oven to 200°C/fan oven 180°C/Gas Mark 6. Grease two baking sheets with a little Trex.
Step 2
Sift the flour and salt into a large mixing bowl and add the cayenne pepper. Rub in the Trex with your fingertips until the mixture looks like fine crumbs. Stir in the cheeses. Beat the egg yolk with 4 tbsp chilled water, then add just enough to the mixture to make a soft, but not sticky, dough.
Step 3
Roll out the pastry on a lightly floured surface to a large oblong. Trim the edges, then cut into strips, measuring about 25cm x 2cm (10in x 3/4in). Place on the prepared sheets, twisting each pastry strip. Gather the trimmings together, re-roll them and make more twists, until the pastry is used up.
Step 4
Lightly brush the strips with any remaining egg mixture, then sprinkle half with poppy seeds and the rest with sesame seeds. Bake for 15-20 minutes until golden brown. Cool, then remove from the baking sheets.
Step 5
Serve with Parma ham, grilled artichokes, sun-blush tomatoes and olives.