Add the mushrooms and spring onions to a frying pan.
Season with salt and pepper then sauté until the mushrooms are golden brown; this should take about 5 minutes.
Add the rosemary and garlic then sauté for 1 more minute.
Add the vegan stock broth then simmer, scraping the bits up from the bottom of the pan, until the sauce has reduced and thickened slightly, this should take another 5 minutes.
Heat 30ml of oil on high in a skillet or a non-stick pan.
Add the defrosted Big Fry Burgers and reduce to medium heat.
Fry for 9 minutes, turning occasionally.
Add vegan cheese slices then allow to melt slightly (don’t let the vegan cheese melt onto the skillet/ pan or it will burn.)
Add the burgers to buns and top them with hummus, baby spinach, pine nuts, sun-dried tomatoes, the juice from the lemons and parsley leaves.
Add the top of the bun and enjoy!