Ricotta cheese is the easiest cheese to make.
I made this for lasagna. I used everything from my Pasta and Tomato Sauce recipe, just adding the ricotta and some cheese. I cut the pasta differently, into big squares, instead of little noodles. Turning Pasta and Tomato Sauce into lasagna brings it up to about $4.00, instead of $2.49, so I don't do it often. It is also more work. But it is one of my husband's favorites, so we occasionally do it in lieu of our the more basic meal.
I'm a little stingy on the ricotta, as I think it doesn't add much to the lasagna, but the mozzarella cheese I add generously. If you love ricotta, you might want to double this recipe.
Heat on low on the stove for ten minutes.
3 cups of milk - $0.48
Add 1/3 cup vinegar (maybe $0.05), and let heat for another ten minutes.
This is a picture of milk curdling. I'm not sure it is more appetizing in color, but if you click on it, you can see. Anyway, see how the milk is separating from the clear liquid around the edges? That's the idea. If the liquid is milky and not clear, add a few more tablespoons of vinegar, like three, and let it heat for ten more minutes.
Now, take a strainer and put some thin cheese cloth or cheese cloth like linen in it. Coffee filters will do, but you'll need a couple. The liquid is whey, which is good for milk in some recipes and also good for lacto-fermenting grains, if you do that (which I often do, but that is a whole other post). If you want to save it, put a large bowl underneath to catch the whey when you strain the curds.
The curds will need to be rinsed so that they don't taste like vinegar. Then, salt the curds. The curds are the ricotta cheese. I originally got this recipe from the Hillbilly Housewife, although she does hers with powdered milk. She has some amazing frugal recipes and tips, in case you haven't checked her out.