Prepare frogs’ legs as described above. Put into skillet, then pour in vermouth. Bring to a boil, then remove from heat. Lift legs from liquid to a plate.
Peel tomatoes, cut in half, and squeeze out seeds and juice. Dice and add to skillet. Add parsley, garlic, oil, sugar, salt, and pepper. Boil liquids 10 minutes to reduce them and concentrate the flavor. Add frogs’ legs and simmer 5 minutes. They are done when flesh turns pearl-white. Do not overcook. The size of the legs will determine length of cooking time. Serve as first course in scallop shells, with crusty bread and a light red Burgundy wine. Allow 2 pairs per person; or, if serving as a main dish, serve with rice and a green salad to 2.