I dont bother with boiled bases anymore,never mind what base i tried i felt there was something missing,so i make my base to taste like a mild curry,i am getting great results by frying the onions very slowly for up too a hour with whole spices,then i cook out garlic,ginger and green chilli paste,i add tomatoes with mixed powder and salt,then i cook the base until it is almost as good as dry and starting to stick too the pan,i add some water and boil for just 10 minutes,and thats it,i could never get the depth of flavor with any base that included boiling the life out of onions spices and what not