Heat oil in a small (approx. 20-24cm) non-stick frying pan over medium high heat. Add mushrooms and cook 2-3 minutes. Add tomatoes and continue cooking until just softened. Season with salt and pepper and transfer to a bowl. Reduce heat to medium.

Whisk eggs and milk together and season with salt and pepper

Sprinkle cheese evenly over the base of the frying pan. Once cheese is melted and bubbling, pour egg mixture over the cheese.

Without stirring or tilting pan. Cook for about 3-4 minutes until set around the edges. Loosen set edges with a heatproof rubber spatula. Cook for a few minutes more until almost set on top, use spatula to loosen from the bottom.

Spoon mushroom and tomato mixture over one side of omelette. Fold omelette over mushrooms and tomatoes. Transfer to a plate. Scatter with basil leaves. Serve immediately with tomato salad.