Keto Classic Spaghetti
A traditional Italian-American pasta dish featuring tender spaghetti topped with a rich, herb-infused marinara sauce. This comforting meal combines aromatic vegetables like onion, garlic, and bell pepper with canned tomatoes, fresh herbs, and warm spices. The sauce simmers gently for 35 minutes, developing deep flavors that coat each strand of pasta perfectly. Ideal for weeknight dinners or casual entertaining, this recipe serves as a satisfying foundation that pairs beautifully with garlic bread and a simple salad. What makes this version special is the addition of fennel seed and the careful balance of fresh and dried herbs.
Ingredients
- 1 medium onion, peeled and chopped
- 2 cloves garlic, peeled and finely chopped
- 1 small green bell pepper, chopped
- 1 tablespoon olive or vegetable oil
- 1 can (14.5 oz) diced tomatoes, undrained
- 1 can (8 oz) tomato sauce
- 1 tablespoon fresh basil leaves, chopped
- 1 ½ teaspoons fresh oregano leaves, chopped
- ¼ teaspoon salt
- ¼ teaspoon fennel seed(optional)
- ⅛ teaspoon pepper
- ½ teaspoon salt, for cooking spaghetti(optional)
- 8 oz uncooked spaghetti
- 1 teaspoon dried basil leaves
- ½ teaspoon dried oregano leaves
- ¼ teaspoon garlic powder
Instructions
- 1
Peel and chop the onion to measure 1/2 cup
- 2
Peel and finely chop the garlic
- 3
Cut the bell pepper in half lengthwise and remove seeds and membrane
- 4
Chop enough bell pepper to measure 1/4 cup
- 5
Heat the oil in a 2-quart saucepan over medium heat for 1 to 2 minutes
- 6
Add the onion, garlic and bell pepper
- 7
Cook for 2 minutes, stirring occasionally
- 8
Stir in the tomatoes with their liquid, tomato sauce, basil, oregano, salt, fennel seed and pepper
- 9
Heat to boiling over high heat
- 10
Reduce heat so mixture bubbles gently and does not spatter
- 11
Cover and cook for 35 minutes, stirring every 10 minutes
- 12
Fill a 4-quart Dutch oven about half full of water after sauce has cooked 20 minutes
- 13
Add salt if desired and cover
- 14
Heat over high heat until water is boiling rapidly
- 15
Add the spaghetti and return to boiling
- 16
Boil uncovered for 8 to 10 minutes, stirring frequently, until tender but not mushy
- 17
Place a strainer or colander in the sink
- 18
Pour the spaghetti in the strainer to drain
- 19
Serve with the tomato sauce
Tips
Stir the sauce every 10 minutes to prevent sticking and ensure gentle bubbling. Lower heat if sauce bubbles too vigorously.
Start the pasta water when the sauce has been cooking for about 20 minutes to time everything perfectly.
Reserve some pasta cooking water before draining - it can help thin the sauce if needed.
Good to Know
Refrigerate leftover sauce for up to 4 days or freeze for up to 3 months. Store cooked pasta separately for up to 3 days.
Sauce can be made up to 2 days ahead and reheated. Cook pasta fresh for best texture.
Serve immediately while hot. Offer grated Parmesan cheese and red pepper flakes on the side.
Common Mistakes
Keep heat low enough so sauce bubbles gently to avoid splattering and burning.
Stir pasta frequently while boiling to prevent sticking together.
Do not overcook pasta - test for doneness starting at 8 minutes.
Substitutions
Vegan Options
Gluten-Free Swaps
FAQ
Can I use fresh tomatoes instead of canned?
Yes, use about 2 pounds fresh tomatoes, peeled and chopped. You may need to cook the sauce longer to reduce excess liquid and concentrate flavors.
What if I don't have fennel seed?
The fennel seed is optional and adds a subtle licorice note. You can omit it completely or substitute with a pinch of Italian seasoning for extra herb flavor.
How long will leftover marinara sauce keep?
Properly stored marinara sauce will keep in the refrigerator for 4-5 days or can be frozen for up to 3 months in airtight containers.