At last, after years of disappointing attempts, I made a good mango pickle.
I really appreciated that wholesome flavor — I could recognize the taste of the sour mango through the pickling spices, and taste the sharpness of mustard oil. And the fennel seeds maintained their crunch.
Step 1: Prepare the mangoes. Start with three big unripe mangoes (Kent is fine) that are still green and hard although they may have grown to their full size. I only say this because it may be difficult to obtain the smaller half-grown ones outside of India (or a farm). Inside, the color should either have no flush of orange at all, or a slight peach tint. Wash them, dry them thoroughly (wait a while so they air dry a bit), then cut them up into half-inch side cubes or whatever that shape is. I don’t feel the need to peel but I did remove the seed. If the mangoes are a lot smaller, cutting right through the seed is fine.
Step 2: Collect whole spices.
Combine 1/3 cup fennel seeds, 3 tbsp fenugreek seeds, 2 tbsp black pepper (whole) and 2 tbsp nigella seeds in a mortar and pestle to crack them slightly (no need to pulverize).
Step 3: Combine mango pieces with dry spices.
Lay out the mango pieces in a flat tray. The idea is that we are going to sun-dry them in this format, so keep that in mind. Put in the whole spices. Also add: 1/2 cup sea salt, couple teaspoons (or more) red chili powder, couple teaspoons turmeric. Mix thoroughly with the mango pieces.
Step 4: Sun-dry for a period of 4-6 days.
So, our mango pieces are coated nicely with the spices. Cover them with a few layers of cheesecloth and put it out in a sunny window. Once a day, open the cloth, give them a stir, spread them out and cover with cheesecloth again.
What is going on with the mango as they sun-dry? You will see them slowly alter: they start to shrivel and turn a little translucent. In fact, they are cooking in slo-mo.
I believe what happens is that the salt draws out the moisture from the mango, and the sun dries them out. In tandem, the sun and the salt are cooking them. When you stir the mango each day, you notice the moisture trapped on the shady side of the pieces, while the top surface — the part that is exposed to the sun — is dry. We turn them to expose all sides to the sun over a period of a few days.
Here is a series of pictures that shows the progression. Day 1 is above.
Do you notice how the mango pieces turn more leathery, more translucent, more shriveled over the days? In essence, they start to cook.
Step 5: Cover with oil
The last step is the easiest — empty the mango pieces into a clean, completely dry glass jar. Pour mustard oil over it until it comes at least a half inch above the topmost layer of mango. Shake the jar to settle the contents. Cover, place in a sunny window for another few days, shaking once each day.