Heat the olive oil using the Instant Pot’s Sauté function or in a skillet over medium heat.

Add the diced onion and cook for 4–5 minutes, stirring occasionally, until softened.

Add the minced garlic and cook for approximately 30 seconds.

Add the ground beef or beef and lamb mixture. Cook, breaking the meat apart, until completely browned and no longer pink.

Season the meat lightly with salt.

Carefully transfer the cooked meat mixture to a food processor. Pulse several times until the meat is finely crumbled but not puréed.

Return the meat to the Instant Pot or slow cooker.

Add the marinara sauce, sugar, Italian seasoning, hot sauce, and additional salt as needed. Stir well.

For the slow-cooker method, cover and cook on high for approximately 3 hours.

For the pressure-cooker method, secure the lid, set the valve to Sealing, and pressure-cook on High for 20 minutes. Allow a 10-minute natural pressure release before carefully releasing the remaining pressure.

Stir the finished sauce. If it is too thin, simmer it uncovered using the Sauté function until it reaches your desired consistency.

Preheat the oven to 180°C or 350°F.

Lightly grease a deep 23 x 33-centimeter or 9 x 13-inch baking dish if needed.

Spread a generous layer of meat sauce evenly across the bottom of the baking dish.

Arrange a layer of no-boil lasagna noodles over the sauce. Break the noodles as needed to fit the dish.

Sprinkle a layer of shredded mozzarella over the noodles.

Spoon a generous layer of meat sauce over the mozzarella, making sure the noodles are completely covered.

Continue layering the noodles, mozzarella, and meat sauce until the ingredients have been used.

Finish with a final layer of sauce and a very generous layer of shredded mozzarella.

Cover the baking dish tightly with aluminum foil. Tent the foil or spray its underside with cooking spray to prevent it from sticking to the cheese.

Bake covered for 30 minutes.

Remove the foil and continue baking for 25–30 minutes, or until the sauce is bubbling and the mozzarella is melted and golden brown.

Remove the lasagna from the oven and let it rest for at least 15–20 minutes before slicing and serving.