Heat the sunflower oil in a large Dutch oven over medium-high heat.

Season the stewing beef with salt and pepper.

Add the beef to the pan in batches and brown on all sides, for 5-6 minutes per batch.

Remove each batch of browned beef to a platter.

Add the halved button mushrooms and thinly sliced onions to the pan.

Cook the mushrooms and onions for 2-3 minutes.

Add the tomato paste, flour, and dried oregano to the pan.

Cook, stirring constantly, for 1 minute.

Return the browned beef to the pan.

Add the vegetable broth and bring to a boil.

Reduce heat, cover, and simmer very gently for 1 1/4-1 1/2 hours, until the beef is tender.

Stir in the drained and sliced roasted red peppers.

Simmer for 10-15 minutes.

Divide the goulash among eight bowls.

Serve with pumpernickel toast, finely chopped fresh parsley, and crème fraîche.