Peel, seed, and chop tomatoes. Slice summer squash and zucchini. Dice potatoes.
Place lamb and vegetables in crockpot. Mix salt, garlic, thyme, and bay leaf into stock; pour over lamb and vegetables. Cover and cook on low 8 hours. (Don't peek. Lifting the lid prolongs cooking time.)
Turn to high. Blend flour and butter, then shape into small balls. Drop into stew and cook, stirring several times, until thickened.
Serve over hot noodles or rice