Step 1

Using a large pot of salted cold water, boil potatoes until fork tender. Remove with a wire spider to a sheet pan to cool.

Step 2

Boil green beans in the salty potato water for 3 - 4 minutes and drain. The green beans should be tender. Run the green beans under cold water or in an ice bath to cool them down.

Step 3

In a bowl, whisk together red onion, garlic, basil, parsley, lemon, mustard and vinegar. Slowly drizzle olive oil into bowl while whisking to emulsify the vinaigrette. Season with salt and pepper.

Step 4

Toss warm potatoes, green beans, mozzarella and tomatoes in vinaigrette. Taste for seasoning and top with parmesan.

Step 5

Enjoy warm or cold.