I think you got your answer but I can't make it through the posts as fast as Kiki adds to them.
Lavender is black underneath and since its recessive it doesn't show if not bred to another lavender or lavender carrier.
So basically its gonna reproduce as a black bird in your situation. Black is dominate to most colors/patterns so it is covering anything the mothers contributed.
Lots of times though one copy of black ends up showing some leakage especially on male offspring. That leakage usually takes some time before it comes so they (or least the males) will probably mature with some color.
Lavender is black underneath and since its recessive it doesn't show if not bred to another lavender or lavender carrier.
So basically its gonna reproduce as a black bird in your situation. Black is dominate to most colors/patterns so it is covering anything the mothers contributed.
Lots of times though one copy of black ends up showing some leakage especially on male offspring. That leakage usually takes some time before it comes so they (or least the males) will probably mature with some color.