Bolognese sauce recipe as it was registered in 1982 with the Bolognese Chamber of Commerce by the organisation of Bolognese chefs/the Italian culinary academy:
-3 table spoons of olive oil or 50g butter
-chopped onion, carrot, celery: 50g each
-300g of passata or cubed tomato, or a table spoon of tomato concentrate. Decent brands are Mutti, Cirio, Elvea
-300g of coarsely ground beef (shoulder or belly)
-100g of bacon, roughly chopped
-half a glass of red wine (about 120 ml). If you don't know which to choose: try Sangiovese.
-a little broth (unspecified, enough to keep the sauce simmering for 2 hours)
-salt and pepper
-1 glass of milk
-optional: half a glass of cream
-Add the bacon to a heated pan, let it take colour.
-Add olive oil or butter, onion, carrot and celery, let them simmer.
-Add the beef, let it take colour, deglaze with the red wine, let it evaporate.
-Add the tomatoes, let the sauce simmer for 2 hours, add broth when necessary. Salt and pepper.
-Add a glass of milk when the sauce is almost ready. Add cream when using dried pasta.
Notes:
-When the recipe was first written down (by Pellegrino Artusi, 1891) there was no cream, milk or tomatoes. According to him you could add porcini though (use a cheaper mushroom if you have to).
-You can add broth first (0.5l, ladle it in like you would with risotto) and halfway through your tomatoes. You'll have a meatier sauce.
-You can add white wine instead of red, and you can do that at half time as well, giving you a lot more flavour from the wine.
-You can add chili pepper with the onion, celery and carrot and leave out the wine for a spicier budget-friendly sauce.
-You don't have to cook it for 2 hours, 1 is sufficient (but not optimal).
-A teaspoon of sugar will counter the acidity of the tomatoes.
-A small table spoon of soy sauce goes well with the heartiness of both tomatoes, meat and cheese.
-Cheese: a 50/50 mix of Swiss Gruyère and Emmenthal was standard until the late 80s, even in Italy. Avoid their French "equivalents" like the plague. Grana Padano is cheaper than Parmigiano and melts (a lot) better; use it 50/50 with Pecorino. The difference in taste is negligible in warm dishes.
-Tomatoes: the only reason San Marzano is renowned is because it's a type of tomato with very little seeds in it, perfect for making canned cubes or passata. If you're looking for taste, go with Pomodorino del Piennolo del Vesuvio or Pomodoro di Pachino. Or any farmer near you who knows what he's doing really.
-You can play with the cuts of meat you add: tongue, cheek, tail… Check out this ragu recipe by Massimo Bottura, Italy's star chef of the past decade: https://www.goodfood.com.au/recipes/massimo-botturas-recipes-for-ragu-and-spaghetti-cetarese-20141017-3ibue
-Herbs and spices are almost never added, but a bay leaf and/or sprig of rosemary wont hurt at all. Chop the rosemary finely or put it in a pouch; when cooking the leaves tend to fall off and they're annoying to chew on.
-Dried pasta: Felicetti, Gentile, Faella or Martelli are among the top brands. Not sure if they make lasagna sheets though.
Happy cooking.