Heat oil in a large skillet over medium heat. Add onion and cook, until soft but not brown. Add garlic and cook for a couple minutes more, still not browning. Add the basil, thyme, and tarragon sprigs, star anise, and clove to a square of cheesecloth and tie with a string. Add the tomatoes and bouquet garni to the pan. Cook, stirring often, until fragrant, about 3 minutes. Remove the cheesecloth with the herbs and spices and discard it. Continue cooking, stirring occasionally, until tomatoes release their juices and a sauce forms, 10-15 minutes. Season sauce with salt and pepper.

Meanwhile, cook spaghetti in a large pot of boiling salted water, stirring occasionally, until al dente. Drain, reserving 1 cup pasta cooking liquid.

Add pasta and ½ cup pasta cooking liquid to sauce in skillet. Cook, tossing and adding more pasta cooking liquid as needed, until sauce coats pasta, about 2 minutes.