Gluten free sausage rolls

Puff pastry

• 300 g unsalted butter cut into pieces (2.5 cm) and frozen
• 140 g potato starch
• 140 g gluten free cornflour plus extra for dusting
• 50 g brown rice flour (see Tips)
• 50 g millet flour (see Tips)
• 2 tsp xanthan gum
• ¼ tsp guar gum (see Tips)
• 1 tsp salt
• 180 g chilled water

Filling

• 1 brown onion (approx. 120 g), cut into halves
• 3 sprigs fresh flat-leaf parsley leaves only
• 20 g olive oil
• 250 g pork mince
• 500 g beef mince
• 1 tbsp white vinegar
• 50 g water
• 30 g tomato sauce (gluten free - see Tips), plus extra to serve
• 1 tsp Dijon mustard (gluten free)
• 1 tsp salt
• ½ tsp ground black pepper
• 2 tsp Worcestershire sauce (gluten free - see Tips), optional
• 1 egg lightly beaten
• sesame seeds black or white, for sprinkling (optional)