Preheat the oven to 220 C. Place the peppers and garlic in a baking tray. Season with salt and pepper and drizzle with oil. Place in the oven for 30-40 minutes, turning occasionally. Fifteen minutes into the cooking time add pricked cherry tomatoes and the beans. While the vegetables are roasting cook the steaks by your favourite method. Once cooked set aside for 5-10 minutes to settle the juices. Slice the beef into strips. To serve put salad leaves onto a serving dish, arrange the roasted vegetables and sliced beef on top. Dress with lemon and mustard mayonnaise.