In a pan put the oil. And cover with the onion petals. Wait until it becomes transparent.
Put the minced garlic. And then add the shrimp. Stir until you get a color.
After that put the arboreo rice (without washing). Stir, letting the rice envelop the entire pan. Gradually add the boiling water, stirring constantly. Until the rice starts to release the starch (it's a. Cream) put the chopped tomatoes, salt (to taste), black pepper (to taste) and green seasonings. Finally, add the butter and stir, with the heat off.
serve right away