Bring 4 quarts of water to a boil. When boiling, add 1 tbsp of salt and cook fettuccine for 12 minutes, or according to the package directions.
2. Step
In a wide skillet, heat olive oil over medium-high heat until the oil is shimmering. Add onion, garlic, and red pepper flakes and cook for 3 to 5 minutes or until the onions are tender.
3. Step
Add flour and stir until combined. Add the tomatoes and the salt and cook over medium-high heat, stirring occasionally, until the sauce has thickened and some liquid has evaporated, about 8 minutes.
4. Step
Drain the fettuccine and toss it with the sauce and fresh basil. Test for seasoning, and add salt and pepper as needed until sauce is adequately seasoned.
