Bring 3 quarts of water to a boil over high heat for the pasta. While you wait for that, let’s make the Pesto Pantesco.
Pulse slivered, toasted almonds in a food processor until the pieces are no bigger than ¼ inch. Add tomatoes, basil, parsley, capers, garlic, salt, and pepper flakes. Pulse until a cohesive mixture forms.
With the food processor running, slowly pour in the olive oil in a steady stream until emulsified. Transfer half of the pesto to a large serving bowl.
Add 2 tablespoons of kosher salt to the boiling water and add the pasta. Cook the pasta, stirring often until al dente, about 8 minutes. Use tongs to transfer the al dente pasta to the serving bowl and top with the remaining pesto.
Toss the pasta and pesto until well combined. Add a little pasta water, a tablespoon at a time, to adjust consistency as needed.