Bring a large pot of salted water to a boil. Add the pasta and cook as the label directs. Reserve 1 1/2 cups cooking water, then drain.

Meanwhile, heat 2 tablespoons olive oil in a large skillet over medium-high heat. Add the chopped fennel bulb and 1/2 teaspoon salt and cook, stirring occasionally, until golden brown, 6 to 8 minutes.

Reduce the heat to medium and add the garlic, tomato paste and red pepper flakes. Cook, stirring, 2 more minutes (add a splash of water if the mixture is sticking).

Stir in the tomato, shrimp, 1/2 teaspoon salt and 1 cup of the reserved cooking water.

Bring to a simmer and cook, stirring occasionally, until the tomatoes are saucy, about 8 more minutes.

Add the pasta and cheese to the sauce and toss to coat. Drizzle with olive oil, season with salt and add more of the reserved pasta water to loosen, if necessary.

Stir in the basil leaves and fennel fronds. Divide among plates.