Keto Heirloom Tomato Basil Spaghetti with Lemon
Light, fresh pasta dish celebrating ripe heirloom tomatoes, fragrant basil, and bright lemon juice. Garlic and red pepper flakes add depth while parmesan brings richness. This version uses minimal cooking to preserve tomato texture and herbaceous notes, making it perfect for summer when tomatoes peak. Serve as a weeknight dinner or light lunch.
Ingredients
- 1 dash olive oil
- 3 heirloom tomato, wholecherry tomato halved or roma tomato1:1vegetarianvegan
works well if heirloom unavailable
- 6 clove garlic, minced or whole
- ¼ cup fresh basil, chopped
- 2 lemon, juiced
- 2 pinch salt
- 2 pinch crushed red pepper flakes
- ½ cup grated parmesan cheese
- 1 pound spaghetti, driedlinguine or fettuccine1:1gluten-free substitution available
gluten-free pasta works with same cook time
Full guide →
Instructions
- 1
Heat olive oil in a pot over medium-high heat.
- 2
Add tomatoes, garlic, and basil; cook until fragrant.
- 3
Add lemon juice and season with salt and red pepper flakes.
- 4
Simmer on medium heat for about 15 minutes.
- 5
Meanwhile, bring salted water to boil in a large pot; cook spaghetti for about 8 minutes until tender.
- 6
Reserve 1/2 cup pasta water before draining.
- 7
Stir reserved pasta water and parmesan into sauce.
- 8
Toss drained spaghetti into sauce until coated.
- 9
Plate and garnish with parmesan and lemon slices.
Tips
Juice lemons fresh and add at the end to preserve brightness; cooked lemon juice becomes bitter.
Use a pasta fork or tongs to toss spaghetti with sauce rather than stirring, which helps it absorb flavor without breaking.
Good to Know
Refrigerate finished pasta up to 2 days in airtight container. Sauce and pasta separate keeps 3 days.
Prepare sauce up to 4 hours ahead; reheat gently. Cook pasta fresh to order or within 2 hours.
Serve immediately while pasta is hot. Accompaniments: crusty bread, fresh basil leaf, lemon wedges, extra parmesan.
Common Mistakes
Do not cook lemon juice in the sauce to avoid bitter flavor; add after cooking.
Do not skip pasta water; starch creates silky emulsion with cheese and oil.
Do not overcook tomatoes; they should remain slightly firm, not disintegrate into mush.
Substitutions
Vegan Options
works well if heirloom unavailable
Gluten-Free Swaps
gluten-free pasta works with same cook time
Full guide →FAQ
Can I use canned tomatoes?
Yes, use 2 cans (14 oz each) crushed or diced heirloom-style canned tomatoes. Reduce simmer time to 10 minutes since they're pre-cooked. Fresh tomatoes deliver superior texture and flavor for this simple dish.
What if I don't have fresh basil?
Dried basil works at 1 tablespoon (one-quarter amount). Add during cooking so it rehydrates. Fresh herbs are ideal; consider frozen basil as second choice, added at the end.
How long can I keep leftovers?
Store sauce and pasta separately up to 3 days refrigerated. Reheat sauce on stovetop with splash of water or pasta water. Reheat pasta briefly in boiling water to refresh texture.