Step 1

Place a medium saucepan over medium heat. Spray with olive oil spray. Add onion and cook, stirring occasionally, for 3-4 minutes or until soft. Add the garlic and mustard seeds, and cook, stirring, for 1 minute or until aromatic.

Step 2

Add the tomato, vinegar and sugar. Bring to the boil. Reduce heat to low. Simmer, stirring occasionally, for 10 minutes or until thick. Set aside to cool.

Step 3

Use the flat side of a meat mallet or a rolling pin to pound each steak until 5mm thick. Heat a large non-stick frying pan over high heat. Spray with olive oil spray to grease. Cook steaks for 1-2 minutes each side for medium or until cooked to your liking. Transfer to a plate. Cover with foil. Set aside for 2 minutes to rest.

Step 4

Meanwhile, toast the bread.

Step 5

Divide half the bread among serving plates. Top with lettuce, steak, beetroot and a dollop of tomato relish. Top with remaining bread to serve.