1. Melt butter in a saucepan and sauté onion until golden brown.
2. Add minced beef to onions and brown. Drain excess fat.
3. On a low heat, add apple cider vinegar. Next, add Worcestershire sauce. Then, add oregano, rosemary, and Italian seasoning. Lastly, add garlic. Stir.
4. Add paste and stir. Next, add diced tomatoes. Lastly, add ketchup, Stir.
5. If needed (which it often will be), add water into sauce. Let simmer on a low heat for about 8-10 minutes, stirring occasionally.
6. Pre-heat oven to 410ºF.
7. In a separate pan, melt 4 tablespoons of butter and vegetable oil together. Add flour and whisk on low heat. Then, add milk gradually and continuously stir. When the rux thickens (or looks like porridge), add milk.
8. Once the rux has reached a custard-like consistency, add salt and pepper. Next, stir in cheese until melted.
9. In a rectangular casserole dish, add in the following order:
Bottom layer: meat sauce
Middle layer: meat-cheese-lasagna (repeat as many times as you can)
Top later: Large amount of cheese sauce
10. Bake in oven uncovered for around 40 minutes, or until lasagna is soft.