Pasta with Chicken and Mushroom Ragù

Very good pasta dish. I had no idea that putting mushrooms and garlic through the food processor before adding them to a dish would so pleasantly intensify their flavors so much, but I'm glad I've discovered this. I will definitely be adding this to my regular pasta rotation.

Pasta with Chicken and Mushroom Ragù
A variation on this recipe from Gourmet

6 ounces cremini mushrooms
3 garlic cloves
1/4 cup extra-virgin olive oil
1 1/4 pounds skinless boneless chicken thighs, cut into 1/2-inch pieces
1 small onion, chopped
3/4 teaspoon chopped rosemary
3 tablespoons balsamic vinegar
1 (28-ounce) can whole tomatoes in juice
1/2 pound dried pappardelle (or other thicker long pasta)
5 ounces baby arugula (about 8 cups)

Pulse mushrooms and garlic in a food processor until finely chopped.

Heat oil in a 12-inch heavy skillet over medium-high heat until it shimmers. Season chicken with 1/2 teaspoon salt and 1/4 teaspoon pepper and cook, stirring occasionally, until just golden, about 3 minutes. Transfer with a slotted spoon to a bowl.

Reduce heat to medium and cook onion, stirring occasionally, until softened, about 3 minutes.

Add mushroom mixture, rosemary, 1/2 teaspoon salt, and 1/4 teaspoon pepper and cook, stirring constantly, until beginning to brown, about 4 minutes.

Add vinegar and cook until evaporated. Add chicken and tomatoes (with juice), then simmer, breaking up tomatoes with a spoon and stirring occasionally, until sauce is just thickened, about 15 minutes.

Meanwhile, cook pasta in a pasta pot of boiling salted water (2 tablespoons salt for 6 quarts water) until al dente.

Add arugula to sauce and stir until wilted. Stir in drained pasta and cook 1 minute.