Yes. In the Ingredients list click the yellow badge showing the quantity and unit (for example "1 oz"). A small Base Weight editor opens where you can type the new base weight and pick a unit, then confirm. The change is saved immediately and the costs and macros of sub-recipes and meals using the ingredient are recalculated. Remember that all prices, stock and macros of the ingredient refer to this base weight, so adjust them if you change the meaning of one unit.