Preheat your oven to 400°F (200°C).
Place the cherry tomatoes on a baking sheet, drizzle with olive oil, and sprinkle with sea salt and black pepper.
Roast the tomatoes for 15-20 minutes until they are soft and have begun to burst.
While tomatoes roast, cook the whole grain penne in a large pot of boiling water according to package directions until al dente.
Drain the pasta, reserving about 2 tablespoons of the starchy cooking water.
In a large skillet over medium heat, add the minced garlic and the pre-cooked shredded chicken, stirring for 1-2 minutes until fragrant.
Add the roasted tomatoes (and any juices from the pan), cooked pasta, and baby spinach to the skillet.
Toss everything together for 1 minute until the spinach is just wilted, adding the reserved pasta water and lemon juice to create a light sauce.
Divide the pasta into bowls and top with freshly grated parmesan cheese.