Step 1

Prepare a barbecue for medium-high cooking over indirect heat. For a gas barbecue, heat one burner on high and leave other burners() off. For a charcoal barbecue, build fire on one side of charcoal grate, leaving other side of barbecue empty.

Step 2

Brush eggplant with 2 tbs oil and season with salt and pepper. Cook on barbecue over lit side for 4 mins each side or until caramelised and tender. Transfer to a plate.

Step 3

Coat steaks with 1 tbs oil and season with salt and pepper. Cook on barbecue over lit side for 2 mins each side for medium-rare doneness. Rest steaks for 5 mins.

Step 4

To make horseradish sauce, in a small bowl, mix mayonnaise, sour cream and horseradish. Season horseradish sauce with salt and pepper.

Step 5

Brush cut sides of bread with remaining 2 tbs oil. Cook on barbecue over lit side for 2 mins or until toasted.

Step 6

Spread horseradish sauce onto cut sides of bread. Place sliced cheese over bottom halves and transfer bottom halves to unlit (empty) side of barbecue and cook with lid closed for 5 mins or until cheese melts.

Step 7

Transfer bottom halves to a cutting board and top with steaks, then with eggplant, tomatoes, rocket and top halves of bread. Cut in half and serve.