Giant Sausage Roll - Cooking like a Boss

preheat oven 200*c							bake for 40 minutes
1 ¹⁄₂ large onion	chopped	mash together in a bowl	lay meat along centre	seal pastry into giant sausage roll shape	flip so join is on bottom	slice air vents in top
562 ¹⁄₂g ⁹⁄₁₆kg 1.24lb 19.8oz sausage meat
255g 0.255kg 0.562lb 8.99oz cheddar cheese	grated
3 tablespoons 0.045 l 45 ml 9 tsp 0.19 cup 0.079 pint tomato puree
6 sundried tomatoes	finely chopped
3 tablespoons 0.045 l 45 ml 9 tsp 0.19 cup 0.079 pint fresh breadcrumbs
1 ¹⁄₂ egg	beaten
480g 0.48kg 1.06lb 16.9oz puff pastry sheet
milk