For the scrambled egg toast with shrimp, toast each one with a slice of cheese. Crack eggs into a bowl, whisk with mineral water, salt and pepper.
Mix in parsley. Peel young onion and cut into fine rings. Melt butter in a small frying pan and fry shrimp and onion for 2-3 minutes, turning.
Pour eggs into skillet and stir gently until mixture sets. Divide scrambled eggs among toasts, garnish with parsley and cherry tomatoes and serve.