In a large pot over low to moderate heat, melt the butter. Add the onions and cook until they start to soften (about 10 minutes), stirring frequently.
Add the garlic, sugar, thyme and vinegar and cook another 5-10 minutes until the onion just starts to caramelise (stir often).
Turn the heat up high and immediately add the white wine (it should sizzle and reduce quickly).
Add the pasta, water and beef stock. Stir and bring to the boil for about 15 minutes or until the pasta is cooked through and the liquid reduced.
If you're pasta is not cooked and the liquid is reduced you can either add more water or turn of the heat and place the lid on the pot for 5 mins.
When the pasta is cooked, stir through the parmesan and parsley, season to taste and enjoy immediately.
Reheat in a pot over low heat until hot.
In an airtight container in the fridge.
