Cook the pasta
Bring a large pot of well-salted water to a boil. Cook the pasta until al dente, reserving 1⁄2 to 1 cup of the pasta cooking water before draining.

Prepare the sauce while pasta cooks
In a large skillet over medium heat, warm the olive oil. Add
the smashed garlic (and red pepper flakes if using) and cook for about 1 minute, just until fragrant.

Add the tomatoes and capers
Add the sliced sun-dried tomatoes and capers. Cook for 2–3 minutes, letting them soften and infuse the oil with flavor.

Build the sauce
Stir in the tomato paste and immediately add 1⁄2 cup of water, stirring until the paste dissolves and forms a light sauce. Remove the garlic clove at this point. Let it simmer briefly while the pasta finishes cooking.

Combine pasta and sauce
Add the drained pasta to the skillet and toss. Gradually add the reserved pasta water (1⁄2 to 1 cup) as needed to coat the pasta evenly.

Finish
Toss in the chopped parsley. Serve immediately with optional grated Pecorino or Parmesan.