Heat oven to 375ºF.
- Heat marinara sauce, bring to a simmer, reduce to low.
Start a large pot of water to boil, add salt. Cook pasta shells about 9 mins. to package directions. Strain on a rack lined baking sheet.
In a large sauté pan, heat over medium high and add extra virgin olive oil. When hot, add sausage, breaking apart with a wooden spoon and cooking until cooked through and no longer pink, about 8 mins.
- Add baby spinach and stir to combine until wilted.
- Turn heat off and immediately add mascarpone cheese, stir to melt, and combine completely into the sausage mixture.
Add about 1 cup of the marinara to the Small Roaster, spread along the entire bottom surface of the pan.
Begin stuffing the shells. Taking a pasta shell, add a large spoonful of the sausage mixture inside and place it seem side down onto the sauce in the roasting pan. Complete this process until all shells are stuffed and lined up.
- Pour remaining marinara over the shells and top with shredded mozzarella.
Cover the pan with foil and bake at 375F for 20 min.
Remove foil, increase oven to 400ºF and bake another 10 min.
- Top with grated parmesan cheese and fresh chopped basil.
