Welcome to Cheftalk.
Dont know how formal youre talking about, or if your 50% is spent first in the BOH, then in the
FOH, or if you're going "back-n-forth" all day.
In the formal banquet room I sous'ed in, the boss/chef/owner had similar responsibilities... she
would go out and hob nob with the clients, then pop back in the kitchen for an hour and cook.
She wore a formal dress mostly, and many of them were.....ex.....SPENSIVE. When in the
kitchen she'd wear a chefcoat over the dress bodice. I never knew her to ruin any dresses, and
she was cooking everything from Marinara sauce to baking cheesecakes.
I would therefore recommend a dark colored cotton dress, about any length, maybe with some
strain resistant treatment, chefcoat over the top, and maybe an apron below that.
Easy-peasy to shuck the chef garb and visit the FOH as a full fledged woman.
As to specially made "chef-dresses" ... beats me, Ive never heard of em.
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