To peel and seed tomatoes, bring a pot of water to a boil, drop in the tomatoes, and boil for about 10 seconds. Remove the tomatoes with a slotted spoon and slip off the skins. Core the tomatoes, cut them into quarters, and squeeze gently to squeeze out the juice and seeds. Blend the tomatoes, garlic, salt, pepper, dry mustard, and lemon juice in a blender or food processor until smooth. Pour into a bowl. Blend the cottage cheese and pickle juice until smooth. Beat together the tomato puree, cottage cheese puree, pickles and egg. Chill to blend flavors for at least 1 hour before serving.