Preheat oven to 425°F. Toss 2 pints cherry tomatoes, the smashed garlic and ½ teaspoon Italian seasoning with 1½ tablespoons oil on a large rimmed baking sheet. Roast until the tomatoes burst and are juicy and lightly caramelized, 18 to 20 minutes.

Meanwhile, bring a medium saucepan of water to a boil. Add 8 ounces penne; cook according to package directions. Drain, reserving ½ cup cooking water.

Heat 1 tablespoon oil in a large skillet over medium-high heat. Add 1 pound ground turkey and ⅛ teaspoon salt; cook, stirring once or twice, until browned and no longer pink, about 5 minutes. Transfer to a bowl; do not wipe the skillet clean.

Add the remaining 1½ tablespoons oil and 1 (8-ounce) package mushrooms to the skillet; arrange in a single layer and cook, undisturbed, until browned on the bottom, about 3 minutes. Stir in ½ teaspoon fennel seed and the remaining ½ teaspoon Italian seasoning; continue to cook, stirring occasionally, until browned all over, about 3 more minutes. Remove from heat and stir in the browned turkey.

Combine 1 cup cottage cheese and ½ cup Parmesan in a mini food processor; process until smooth, 15 to 20 seconds.

Scrape the roasted tomatoes, garlic and any accumulated juices from the pan into the skillet with the turkey mixture. Stir everything together, scraping up any browned bits from the bottom of the skillet. Add ½ cup cottage cheese mixture, ¼ cup reserved cooking water and the remaining ¼ teaspoon salt; stir until fully incorporated. Fold in the pasta; cook over medium-high heat, stirring often and adding the remaining ¼ cup reserved cooking water, 1 tablespoon at a time, as needed, until the pasta is evenly coated and the sauce clings to the pasta, 1 to 2 minutes.

Divide the pasta among 4 bowls and dollop with the remaining cottage cheese mixture. Garnish with oregano, if desired.