1 Lightly spray a large chargrill pan with olive oil. Place pan over medium-high heat. Cook the capsicum and zucchini, turning, for 5–7 minutes, or until lightly charred and tender. Transfer the vegetables to a plate.
2 Lightly spray cut side of bread with olive oil. Grill the bread for 2–3 minutes, or until golden and toasted. Transfer to a board.
3 Spray grill pan again with oil. Cook steaks for 1 minute each side, or until they are cooked to your liking. Season with cracked pepper. Transfer the steaks to a plate and thickly slice.
4 Meanwhile, combine yoghurt, lemon juice and mustards in bowl.
5 To assemble, top base of the bread with a little of the mustard yoghurt. Layer with salad leaves, charred vegetables, beef and the remaining mustard yoghurt. Sandwich with roll top. Cut into four portions and serve.