Roughly chop the rocket and scatter in on a serving plate.
Finely slice any nasturtium leaves and scatter them over the plate. Pull the flowers into petals and scatter them over the plate too.
Halve or quarter the tomatoes, depending on how large they are. Arrange them on the serving plate.
Peel and crush the garlic. Whisk it with the mustard, vinegar and 1 tbsp olive oil. Add a pinch of salt and pepper and whisk again. Taste and adjust the seasoning.
Drizzle the dressing over the salad and serve.