Submarine sandwiches with steak and pepperoni

In a bowl, whisk together all ingredients. Season with salt and pepper. Set aside for later use.

Preheat oven to 200°C (400°F).

Heat a large non-stick frying pan with the oil over high heat, add the onions, mushrooms and peppers and cook, stirring, for three minutes. Season with salt and pepper. Set aside.

In the same skillet, add steak, cook for three minutes, add pepperoni, cook for another minute and season with oregano, salt and pepper. Keep warm.

Cut the buns in half and place on a baking sheet lined with parchment paper. Divide steak, pepperoni and vegetables among buns. Sprinkle with cheese and bake for a few minutes or until cheese is melted.

Cover submarines with lettuce and tomato slices.

Drizzle with vinaigrette to taste and serve immediately.