Boil the water (use large pot with low rim, so that all anchovies have the same chance) with garlic clove, 2 bay leaves and salt until boils. Add vinegar and remove the pot from fire.
Add anchovies in that hot water and keep them inside not more than 2 minutes. When meat starts to separate from bones it’s done (you have to take them out just before this happens).
Using hollow spoon remove the anchovies from water and put them in a bowl.
Before you put them in a bowl, slice the onion into rounds and arrange them to cover the bottom (take also large bowl with low rim).
Spread rosemary leaves, capers, black pepper berries, bay leaves over onion and than put anchovies over. Pour olive oil over anchovies. Slice lemon into rings and arrange rings to cover anchovies. You can put just some of cooked water over if you want to keep them in refrigerator.
Cool the salad and serve.
You can keep the salad in refrigerator up to 4 days.