That's the hardest ingredient to find; you'll have to look at groceries that import Mediterranean food. Tarama is usually sold in larger jars, but you can store the remainder in the freezer for months (even beyond the printed expiration date). You'll also need
Boil the potatoes in water. Boiling potatoes requires just enough water to cover them up. If you cut up the potatoes first, they will boil faster; hi heat and a covered pot will also help. The potatoes need to boil as long as it takes for them to be soft all the way down to their core. When they are soft, take them out of the water, and peel them.
Instead of potatoes, you can use bread instead. In that case, use
The catch is that you have to wait until the bread is stale. Then, you should get rid of the crust and soak the bread's interior in water. Then, you must drain the bread and leave it on an absorbent paper towel to dry thoroughly. I prefer potatoes because the recipe is simpler and because I like the mix of the potato/tarama-salad flavor.
In a mixing bowl, mash together the potatoes (or bread) with the tarama. Add
Some recipes recommend putting 1 tbsp (or more), but that's a matter of taste. It's very important that the onion is dried up, which is why it's best to use onion powder or dried onion (sold as spices) instead of starting with a fresh onion.
It's best that you use an electric mixer or blender for the mixing as you have to mix the ingredients very well. While doing so, add gradually (i.e. you pour in six equal doses and mix until fully absorbed before the next dosage)
If you just dump them in, and then mix, the mixture is likely to turn into an eternal sea of oil with clumps of potato and tarama (and there's no cure from that). If you mix in gradually, though, the mixture will turn into a very nice, smooth dip. If the mixture peaks, then pour in a little water until it's smooth again.
Chill the taramosalata in the refrigerator for a few hours (keep covered or the top will form a crust), and then serve cold.