Bring a large pot of heavily salted water to a rapid boil. Cook the pasta according to package instructions until al dente. Reserve 120 ml of starchy pasta water, then drain the pasta and set aside.

Pat chicken pieces dry with paper towels. Season evenly with kosher salt, freshly ground black pepper, and dried oregano.

Heat 15 ml of olive oil in a wide, high-sided skillet over medium-high heat. Add the chicken pieces in a single layer and sear for 5 to 6 minutes, flipping once, until browned and cooked through to an internal temperature of 74 °C (74 °C). Transfer chicken to a clean plate.

Lower the skillet heat to medium. Add the remaining olive oil and unsalted butter. Once melted, stir in the minced garlic, sun-dried tomatoes, and crushed red pepper flakes, sautéing for about 1 minute until fragrant.

Pour in the chicken broth, using a wooden spoon to scrape up any browned bits stuck to the bottom of the skillet. Stir in the heavy cream and bring to a gentle simmer.

Reduce heat to low and gradually whisk in the freshly grated Parmesan until melted and creamy. Simmer gently for 2 minutes until the sauce slightly thickens.

Add the cooked chicken, drained pasta, and fresh baby spinach to the pan. Toss continuously for 2 minutes until the spinach wilts and the sauce evenly coats the pasta. If the sauce is too thick, splash in 1 to 30 ml of reserved pasta water.

Remove from heat, garnish with chopped fresh basil and extra grated Parmesan, and serve immediately warm.