Preheat the oven to 400F.
Bring a salted pot of water to a boil and cook the noodles according to the package instructions. Use tongs to transfer the noodles to a plate or sheet pan to cool.
In a large oven-proof skillet (recommend a 12” cast-iron) over medium-high heat, add the oil and sausage. Break the sausage into chunks, then let it cook undisturbed for 3-5 minutes, or until browned. Give the sausage a stir to release from the pan and continue to cook until cooked through, breaking up into smaller chunks as it cooks, about 2 more minutes. Transfer to a paper towel lined plate or bowl.
Remove any excess oil from the skillet (tilt the pan and use a spoon to remove). You just need enough oil to lightly coat the pan. To the skillet over medium-high heat, add the greens, cauliflower, and salt and cook until the greens have softened and water has evaporated, about 3-5 minutes. Turn off the heat.
Stir the sausage back into the skillet, then spread into an even layer. Tear the lasagna noodles into pieces and loosely nestle them into the skillet (see video). Pour the marinara evenly over top, use a spoon to spread it around, and give the pan a shake so the marinara can evenly distribute.
Top with dollops of ricotta, then sprinkle the mozzarella evenly over top.
Bake for 10-15 minutes, or until the skillet is sizzling and cheese is melted. Option to put it under the broiler for 1-2 minutes at the end to get some browning on top.
Serve topped with fresh herbs, if using.