Preheat the oven to 180C/350F/Gas 4.
For the mushroom, cheese and steak stack, drizzle a little olive oil over the Portobello mushrooms. Heat a frying pan over a medium heat and fry the mushrooms for 4-5 minutes on each side, until softened. Remove from the pan and set aside to keep warm.
Add a little more oil to the pan and heat until very hot. Season the steak on both sides with salt and freshly ground black pepper and fry for 1-2 minutes on each side, or until cooked to your liking.
Place one Portobello mushroom onto a baking sheet and top with one of the steak pieces and half the cheese. Place another Portobello mushroom on top of the cheese, followed by the other piece of steak, the rest of the cheese and finally the third mushroom. Secure with a wooden skewer and place in the oven for 6-8 minutes, or until the cheese is melted.
For the dressing, heat the olive oil in a small pan over a medium heat and fry the red pepper for 3-4 minutes. Add the garlic and cook for a further minute. Add the water, wine and sugar, season with salt and freshly ground black pepper and simmer for 3-4 minutes. Add the parsley, then blend the mixture with a hand blender until almost smooth.
To serve, place the mushroom stack onto a serving plate and pour over the dressing.