B85 Beef Sausage Rolls - with jalapeño and cheese

Bahan-bahan (4 porsi)

• 1 small onion (, peeled, whole)
• 1/2 cup panko breadcrumbs ((Note 1))
• 500 g /1 lb beef mince ((ground beef), fattier the better)
• 1 egg
• 2 g arlic cloves (, minced with garlic press or finely grated)
• 1 beef stock cube (, crumbled (OXO is my favourite) or 1/2 tsp cooking salt / kosher salt)
• 1/2 tsp cooking salt / kosher salt ((halve for table salt, +25% for flakes))
• 1/4 tsp black pepper
• 1/3 cup pickled jalapeno (, roughly chopped (~3mm) (Note 2))
• 1 1/2 cups (150g) cheddar (, shredded, or other cheese of choice (Note 3), pre-shredded ok)
• 1/2 cup (50g) parmesan (, shredded using box grater (pre-shredded ok))
• 2 sheets frozen puff pastry (, butter is better (24cm / 9.5" squares) (Note 4))
• 1 egg (, separated)
• 1 tsp white sesame seeds
• 1/2 tsp black sesame seeds ((or more white))
• Aussie tomato sauce or ketchup