Heat a skillet over a medium heat and add in a drizzle of olive oil, then add the diced onion, garlic, celery, carrots and the ground beef. Stir it all together and cook until the beef has browned.

Pour in the marinara sauce along with the Italian herbs and a pinch of salt and pepper. Stir it all together and let it simmer over a low heat for 30 minutes or until it is lovely and thick and saucy.

While the meat sauce cooks, make your white sauce by melting the butter into a small saucepan. Use a whisk to add the flour in to the butter and whisk to make a smooth roux.

Slowly pour the whole milk into the saucepan and then keep whisking over a low heat until it thickens. Be sure to keep a close eye on it, otherwise it will become lumpy.

To assemble the lasagna in the skillet scoop out half the meat sauce. Then add a single layer of lasagna sheets. You can break them to fit into the skillet. Then add a layer of the white sauce and smooth out. Repeat this for another layer.