Hummus's key ingredient, according to Spooner, is fruit of mallow (4-6)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Spoonerism of CHICK-PEAS (the main ingredient in hummus). No, I’d never heard of a name for the fruit of the mallow plant, but it’s in Chambers – and from the wordplay it couldn’t really be anything else.