Cut the green onions diagonally into thick slices. Peel the garlic and mince. Clean the scallops.
Put the frozen peas in a sieve and pour a cup of boiling water over them.
Heat a tablespoon of olive oil in a medium skillet over a medium-low heat. Add the green onions and let them sweat gently for about a minute, until soft. Add the peas and toss for another minute or two. Season with salt and pepper. Remove from the pan and set aside.
Add another tablespoon of oil and turn the heat up high.
Season the scallops with salt and pepper and when the pan is very hot; they should sizzle when the hit the pan. Leave them for about 1 minute, then carefully turn one over. If it’s golden brown, flip all the scallops over and cook until caramelized on the other side.
Reduce the heat to medium-low and return the peas and green onions to the pan, along with the butter (if using) and garlic.
Toss, remove from the heat, and add a squeeze of lemon.