Heat 3 tablespoons of olive oil in a large saucepan.

Add the chopped onion and cook over medium-high heat until softened, about 2 minutes.

Add the minced garlic and cook, stirring, until fragrant, about 1 minute.

Add the farro and stir until coated with oil, about 1 minute.

Add the dry white wine and simmer until almost evaporated, about 2 minutes.

Lower the heat to medium.

Add 1 cup of water and cook, stirring, until absorbed.

Repeat adding 1 cup of water at a time, stirring constantly, until the farro is just tender and suspended in a creamy sauce, about 30 minutes total.

Stir the chopped tomatoes into the risotto and bring to a boil over medium heat.

Remove from the heat.

Stir in the remaining 1 tablespoon of olive oil and the grated Parmigiano-Reggiano cheese.

Season with salt and freshly ground pepper to taste.

Spoon the risotto into bowls.

Garnish with sliced basil leaves.

Serve hot.