Step 1: Boil Lasagna Noodles

In a large pot with salted boiling water, add the lasagna noodles. Cook them according to package directions minus 1.5 minutes. This ensures they are al dente and flexible for rolling.

Step 2: Prepare Spinach & Ricotta Filling

In a mixing bowl, add ricotta cheese (drained if too wet), a beaten egg, 1/2 cup grated mozzarella cheese, 1/2 cup grated Grana Padano cheese, 1 cup chopped spinach, 1/2 tsp garlic salt, and 1/4 tsp freshly ground black pepper. Stir until all ingredients are nicely combined. Set aside.

Step 3: Cool Lasagna Noodles

Once cooked, drain the noodles well in a colander. Transfer them to a large bowl and fill it with cold water. Gently shake the noodles to stop the cooking process and prevent them from sticking together. Leave them in the cold water until needed.

Step 4: Sauté Onions

In a large skillet over medium heat, add 2 tbsp olive oil. Once the oil is hot, add 1 cup diced white onions and season with 1/4 tsp ground sea salt. Sauté for 1 minute.

Step 5: Add Red Peppers

Add 1/2 cup diced red bell peppers to the skillet. Sauté for 2 minutes, stirring occasionally.

Step 6: Add Mushrooms

Add 1 cup diced cremini mushrooms to the skillet. Blend them with the other vegetables and season generously with 1/2 tsp freshly ground black pepper. Cook for about 5 minutes, stirring often.

Step 7: Brown Ground Beef

Add 1 lb lean ground beef to the skillet. Break the meat into very small pieces using a kitchen tool. Cook until the meat is no longer pink.

Step 8: Add Garlic and Marinara Sauce

Halfway through cooking the beef, add 2 cloves of pressed garlic. Continue sautéing until the meat is fully cooked. Then, add 24 oz marinara sauce, 1 tsp Italian seasoning, and 1/4 tsp red pepper flakes. Stir very well to combine all ingredients.

Step 9: Simmer Meat Sauce

Bring the meat sauce mixture to a simmer. Place the lid slightly ajar on the skillet and let it cook for 5 minutes to allow the flavors to meld and prevent splashing.

Step 10: Prepare Baking Dish

Remove the meat sauce from the heat. Ladle about 1/3 of the meat sauce into a 9x13 inch baking dish that has been greased with cooking spray. Spread it out evenly to cover the bottom of the dish. Set aside.

Step 11: Fill Lasagna Noodles

Lay the cooked lasagna noodles flat on a large baking sheet. Using a measuring scoop, place the spinach and ricotta filling on each noodle. Spread it out evenly, leaving about 1 inch of space on both ends and some on each side of the noodles.

Step 12: Add Meat Sauce to Noodles

Next, spread about 1/3 of the meat sauce over the spinach filling on each noodle, leaving the same spacing as the spinach. This helps prevent the mixture from being pushed out when rolling.

Step 13: Roll Up Lasagna

Starting from one end, carefully roll up each filled lasagna noodle to the other end, creating individual roll-ups.

Step 14: Arrange in Baking Dish

Transfer the rolled-up lasagna noodles to the prepared baking dish, placing them seam-side down.

Step 15: Top with Remaining Sauce and Cheese

Spoon the remaining 1/3 of the meat sauce on top of the roll-ups and spread it out evenly. Sprinkle with 1/2 cup grated mozzarella cheese, followed by 1/2 cup grated Grana Padano cheese (or Parmesan).

Step 16: Bake Covered

Cover the baking dish with aluminum foil that has been greased on the underside (to prevent cheese from sticking). Transfer the dish to a 375°F (190°C) preheated oven and bake for 20 minutes.

Step 17: Bake Uncovered

Carefully remove the foil from the dish. Return it to the oven and bake for an additional 10 minutes, or until the cheeses are melted and the top is golden brown.

Step 18: Rest and Serve

Once baked, remove the dish from the oven. Let it rest for 10 minutes before sprinkling on some fresh chopped parsley for garnish. Serve warm.

• Drain ricotta cheese for a few hours if it's too wet to ensure a firmer filling.

• When simmering tomato sauce, place the lid slightly ajar to prevent splashing.

• Leaving space on the noodles when spreading filling prevents it from being pushed out during rolling.

• Substitute Grana Padano cheese with Parmesan cheese.

• Make your own marinara sauce from scratch for a personalized flavor.

• Use regular lasagna noodles instead of ribbed for a neater appearance if preferred.