These spinach and ricotta stuffed shells are such a comforting, flavorful dinner! To get ahead, you can stuff the shells and place them in the baking dish with the marinara up to 4 hours in advance. Cover with foil and store them in the fridge until you're ready to serve. Then, just bake and eat!
Place the spinach in a steamer basket and set over a pot with 1-inch of water. Bring the water to a simmer, cover, and let steam for 1 minute, until the spinach is wilted. Transfer to a strainer and squeeze out the excess water and chop the spinach.
In a large pot of salted boiling water, cook the pasta shells for 10 minutes, until al dente. Drain and drizzle with a little olive oil to keep them from sticking together.
In a medium bowl, combine the spinach with the ricotta, pecorino, garlic, oregano, lemon zest, red pepper flakes, salt, and several grinds of pepper.
Spread the marinara in the bottom of a 9x13 baking dish. Stuff each shell with the filling and place in the dish. Cover with foil and bake for 20 minutes. Serve with more marinara on the side.
Notes
*Our favorite store-bought marinara sauce is Rao's Marinara.This recipe freezes well! After you've assembled the shells in the baking dish, cover with foil and freeze. To thaw, transfer the dish to the fridge about 10 hours before you plan to serve (i.e. the morning that you plan to serve them for dinner). Remove from the fridge and let sit at room temp while the oven preheats. Bake, covered, for 30 minutes, or until thawed and warmed through.