Complains wood also filled with dull fruit (15)

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

BEEFS (beef, as a verb = complain) + TEAK (a type of wood), then TOO (also) filled with MAT (variant spelling of matt = not shiny = dull). A very large tomato, which is botanically a fruit but usually treated as a vegetable. I can’t help thinking “dull” is appropriate; let’s just say they’re usually bred for size rather than taste.