Any house in U.S will have peanut butter in the pantry. Unless there is someone with peanut allergy in the house. I can say the same about South Indian Homes with regard to pickle. If not anything, one can eat rice mixed with yogurt topped with pickle. It is that common and an essential pantry item.
For some reason, I never developed interest in pickles. But, my relatives (actually my husband's side of the family) are too much into pickles. Even when I am not fond of them, I have been making pickles for a few years now. This one is a recipe from my father-in-law. He can give you recipe for any South Indian food. Problem is he talks about one ingredient in number, the other in kilograms the other in some kind of measure which I don't have available here. I just asked him what the ingredients are and came up with the recipe. When you talk about 20 limes, people are not paying attention to how big they are. I have seen limes twice the size of limes we get in India. To make it easy, I converted everything into cups. You can increase the chillies if you like the pickle with more heat.
Mango Milk Shake
Limes - Quartered or cut into eighths if big and measured 8 cups
Limes - 4 - 6 for juicing
Salt - 1 1/2 cups (Go easy on it in the beginning - start with 1 cup)
Green chillies - stalks removed and measured 4 cups
Ginger - Peeled and diced small and then measured 2 cups
Fenugreek seeds / Methi - 1/4 cup
Asafoetida / Hing - size of a pea
Oil - 1 cup (I used mustard oil but you can use any flavorless oil)
Mustard seeds - 1 TBSP
Turmeric - 2 heaping tsp
Wash limes well and pat them dry. Cut them into 8th if big or quarter them if small. Place them in a clean, dry glass jar or a porcelain dish which has a lid. Place a layer of limes, sprinkle salt, another layer of limes, salt and keep repeating this till all are used up.
Remove the stalks from green chillies. Wash and dry on a paper towel. Measure and after measuring, chop them into thirds or halves. Add it to the lime and salt mixture. Squeeze the remaining limes reserved for juicing into the pot. Mix the chopped ginger and mix well. Cover with the lid and let it sit for 2 weeks. Every other day, stir with a clean and dry spatula.
At the end of 2 weeks, stir and taste a piece. If it has become soft and has absorbed the salt, it is ready to be seasoned. Some limes have thicker skin and they might take a little longer. You should be able to bite into the lime easily.
Don't leave a stainless steel or metal spoon in the container. Salt will affect the metal. Do not store the pickle in any metal container either. Glass or ceramic or plastic containers are the best to store pickles.