Excel help

Hello,

I am having trouble with an excel calculation, i'd be grateful for any help:

I have menu items listed along the top, with a space for the unit cost below
& the ingredients of the menu down the side with the size of packs alongside that
I will be filling the amount of ingredient used to make that menu item and I want the calculation to go down that list and where there has been a value entered I want it to add up the ingredient prices that go to make that menu item??!!!! Bit confusing I'll try and show you:


MENU ITEMS
coffee tea cheese sandwich
INGREDIENT PACK SIZE WEIGHTg COST unit cost £0.00 £0.00 £0.00
bread 1 x 200 £1.00 100
cheese 1 x 1000 £2.00 60
coffee 1 x 1000 £10.00 50
tea bag 100 x 20 £4.00 50
onion 1 x 5000 £2.00 20


These are just examples but you can see that to make a coffee here i need 50g of coffee, i would like the calculation to go down the list of ingredients and where it meets a value calculate the cost of (in this case 50g of coffee) and return it to the unit cost (currently showing £0.00) at the top
Obviously this gets more complicated for a multi ingredient item, like the cheese sandwich, is there a way it could calculate 100g of bread, 60g of cheese and 20g of onion and place the sum of them in the unit cost at the top?
Please be aware this is a simplified example and the figures are not correct, in reality there may be 10 ingredients in one menu item so i'll need it to calculate them all and then add them up.

Would i be better having excel first calculate the price of 1g of each ingredient then put that figure elsewhere and then refer back to that when doing calculations or is there a real easy way?

Thanks for your advice.

Matthew