when i was in bordeaux i spent one day walking from bookshop and bookshop and simply perusing. there was one book that i wish i would have bought that i read from cover to cover while window shopping. it was a book on how to make chevre (goat milk cheese). it looked like it would be fairly simple, requiring only goat's milk, vinegar, molds, and a little patience. later, while searching the internet to try and find a similar set of instructions i found that ricotta seemed to be the entry level into cheesemaking and figured that i would give it a try before devoting a few days to making mozzarella or chevre. but i didn't think it would be so easy! it only takes like 15 minutes tops! it's pretty safe to say that i'm never buying ricotta at the store ever again.
this is everything you need to make ricotta cheese.
2 cups pasteurized (not UHT or ultra-pasteurized) whole milk
2 tbsp. distilled white vinegar
1/4 tsp. salt
this makes about 3/4 cup ricotta, so double, triple, etc...the amounts as needed.

it's important to use regular pasteurized milk as opposed to UHT or ultra-pasteurized (which is usually used for organic milk) because Ultra High Temperature milk has been briefly heated to 275° F and doesn't work well for making cheese (via
thefoodlab). you can also use buttermilk or lemon juice in place of vinegar, and
thefoodlab made a few different batches to compare.

add the milk and salt into a saucepan and heat on medium/high. stir continuously to prevent the milk from sticking to the pan and/or forming a skin.
right before the milk begins to boil, remove the pot from the burner and add the vinegar, then slowly stir for one minute. when stirring, do not separate the curds, which will almost immediately begin to form.

after the minute is up, place a towel over the saucepan for a few minutes to allow it to rest. pour the curds and whey into a colander lined with a few layers of cheesecloth, a thin dish towel, or damp (not sopping) paper towels to drain.
the amount of time you let the cheese drain is up to you
thefoodlab suggests about 5 minutes for creamy curds, 15-20 for a spreadable, but not runny consistency, and and 2+ hours to overnight for dry, crumbly curds.
i let mine drain for about 5 minutes before i couldn't help myself and had to try a spoonful with a drizzle of honey. it was AMAZING.