Marinade: Mix the olive oil, dried rosemary, garlic and pepper to taste. Add the steaks then leave for at least 1 hour or overnight in the fridge.
When the steak is marinated preheat your oven to 250 degrees C.
Sauce: Make a 2cm x 2cm slit underneath the 3 capsicums to insert a clove of garlic each. Roast the capsicums and onion on an oven tray with a tablespoon of oil for 1 hour turning every 15 minutes.
Meanwhile at minute 45 cook the steak in a hot frying pan for 4 minutes each side (medium). Set aside when done.
After 1 hour seed and skin the roasted capsicums. Peel the roasted garlic and onion. In a food processor or a ricer mash the red capsicum, garlic, onion, salt and pepper. It should be a sauce consistency.
Spoon the sauce on the plate and put the steak on top.