10 across
The
writer’s
penning
line
as
children’s
author
(5)
The writer’s penning line as children’s author (5)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
Look at children's author at the end — that's your definition, pointing to A.A. Milne. "The writer's" gives you MINE (as in belonging to the setter), and that word *pens* — i.e., contains — L (the standard abbreviation for line). So MINE wraps around L to give you MI-L-NE.