I sometimes make clams for appetisers, but they are hard to find where I live, while blue mussels are easier to find and very cheap. The only problem is they are only sold in 1kg quantities, and last time I tried to prepare that much the results were bad.
When I make clams as appetisers, after a Portuguese recipe I found, I just put oil with some herbs in the bottom of the pot, and the clams only cover the bottom of the pot. No liquid at all. The results are perfect, and far better than I ever had with larger quantities of mussels and with liquid in the pot. With larger quantities plus some liquid I end up with the bottom shells overcooked and soggy.
Also, having to add white wine makes it much more expensive where I live, so it becomes a party meal rather than the everyday meal I want. I don’t drink wine, so it means buying one full bottle just to make the mussels.
So, how high can you "stack" mussels in the pot, while making sure they are all cooked perfectly, and can it be done without liquid, or at least without wine? I guess I could steam them in several batches to avoid filling the pot too high. Mussels recipes I find online seem contradictory: They tell me the mussels should be steamed and not boiled. Then they tell me to add up to one inch of liquid in the pot. That makes no sense, because then the bottom mussels will be boiled.