Combine onion, olives, capers, garlic, ½ teaspoon salt, and a few grinds pepper in an 8 X 8-inch baking dish.
Stir in 1 tablespoon olive oil. Then top mixture with thyme sprigs.
Core tomatoes, then lightly score an "X" on both ends. Cut in half, then place cut side down on top of thyme sprigs. Drizzle tomatoes with remaining tablespoon olive oil.
Bake until tomato skins are shriveled and onions are tender (about 35 to 40 minutes).
Remove and discard tomato skins, then carefully transfer tomatoes to blender (or food processor). Remove thyme sprigs, then add onion mixture to blender as well.
Pulse sauce a few times or until chunky. Stir in thyme leaves, and season to taste with salt and pepper.
Prepare Pasta:
About 10 minutes before sauce is done roasting, bring a large pot of well-salted water to a boil, then add pasta. Cook pasta until al dente.
Remove ½ cup pasta cooking water from pot; set aside. Drain pasta.
Return pasta to pot over medium heat, then add sauce and a small splash of pasta water. Toss pasta and sauce for a few minutes, until pasta is coated with sauce (add more pasta water if needed).
Stir in fresh basil and season to taste with salt and pepper.
Serve pasta immediately. Enjoy!
Notes
For best results, use the freshest, tastiest tomatoes you can find. I used heirloom tomatoes, but tomatoes fresh from the garden or farmers market will also work great.I like making this pasta recipe with spaghetti, but almost any shape will work, from linguine to penne.You can blend this sauce to exactly your preferred texture. Prefer a chunkier sauce? Pulse just a few times. Prefer a more uniform sauce? Blend until smooth.Make sure to check out the info before this recipe card for helpful tips, variations, serving suggestions, and more!