Build or prepare your campfire and allow it to burn down to a solid bed of glowing coals — you want heat, not flames. Position your 12-inch dutch oven over the coals to preheat for 3–4 minutes.

Add the Italian sausage to the preheated dutch oven and cook, breaking it up with a spoon, until browned and cooked through, about 8–10 minutes.

Add the diced onion to the sausage and cook for 3–4 minutes until softened. Add the minced garlic and Italian seasoning and cook for 1 minute more, stirring constantly.

Pour in the jarred marinara sauce and water or broth. Stir to combine everything well. Taste and adjust seasoning. Remove from heat and transfer the meat sauce to a separate bowl or pot to cool slightly. Wipe the dutch oven clean with a paper towel (carefully — it's hot).

In a bowl, combine the ricotta, beaten egg, salt, black pepper, parsley, and ¼ cup each of the shredded mozzarella and Parmesan. Mix until smooth and well combined.

Lightly grease the inside bottom and sides of the dutch oven with cooking spray or a thin film of olive oil.

Spread about ½ cup of meat sauce on the bottom of the dutch oven to prevent sticking.

Layer 3 no-boil lasagna noodles over the sauce, breaking them as needed to fill the round pot in a single layer.

Spread half of the ricotta mixture evenly over the noodles.

Spoon one-third of the remaining meat sauce over the ricotta layer.

Sprinkle ½ cup of shredded mozzarella over the sauce.

Add another layer of 3 noodles (broken to fit), then spread the remaining ricotta mixture, followed by another one-third of the meat sauce and another ½ cup of mozzarella.

Add a final layer of noodles, the remaining meat sauce, the remaining mozzarella, and finish with the remaining Parmesan cheese on top.

Secure the lid tightly on the dutch oven. Using a shovel or tongs, carefully place 8 coals underneath the dutch oven and pile 14–16 coals on top of the lid.

Cook for 35–45 minutes, rotating the dutch oven a quarter turn every 10 minutes for even heat distribution. Avoid lifting the lid more than once to check, as heat escapes quickly.

At the 35-minute mark, carefully lift the lid to check — the lasagna is done when the noodles are tender when pierced with a knife, the cheese is melted and beginning to brown, and the sauce is bubbling around the edges.

Remove the dutch oven from the coals. Let the lasagna rest with the lid on for 10 minutes before serving — this helps it set up so it slices cleanly. Serve directly from the pot.