be a dab hand
To be skilled in a particular area. Primarily heard in UK, Australia. Amanda can fix that hole in your blouse—she's a dab hand at sewing.
be a dab hand at
be expert at. Dab in this sense is recorded since the late 17th century, but its origin is unknown.
1998 Bookseller Stephanie Cabot…is apparently a dab hand at milking cows, according to one of those mystifying diary items in Skateboarders' Weekly.
be a dab ˈhand at something/at doing something
(British English, informal) be very good at doing something: Ask Neil to do it — he’s a dab hand at carpentry.