An article in the Guardian tipped me off to an exhibition, For Tove Jansson To Paint Was To Be. It is now at the Didrichsen Art Museum in Helsinki, Finland, where it originates, and will be going to Paris. How I wish I could see it in either place!
Tove Jansson is best known for her wonderful Moomin characters, but as this painting of a picnic shows, she was a great stylist. In fact, her wit and refusal to go namby-pamby in her work for children is what makes the Moomin books vital for adults as well as children (even if subsequent commericialization has descended into cuddliness). You can see what I mean by clicking on "Take a look inside" at Macmillan's page for Comet in Moominland.
She was also a great writer. The Summer Book, the story of a little girl's time spent on an island with her eccentric grandmother, is my favorite of her books for adults, but anything she wrote—or drew or painted—is worth investigation.