Spontaneous — Diana Wagman

When Auntie Ned spontaneously combusts, she leaves behind a pair of smoking orthopedic shoes and a house that she wills to her best friend's daughters. Amy and Gwendolyn are sisters--closer than close--who move into Ned's bungalow and inherit her legacies: a closet full of housedresses, a freezer full of meat, and the passionate flames of unrequited desire.

Amy's appetites--for meat, for sex, for getting her way--are ferocious, while Gwendolyn longs for a more normal existence but can't refuse her big sister anything at all. Not the intrusion of Dr. Minor, Professor of Pyrophenomena, who has come to investigate Auntie Ned's death. And not the presence in their bed of Roosevelt, a troubled carpenter whose steamy entanglement with the sisters will either save them all or create a situation that's bound to combust.

...a good Hollywood thriller... as well done as an exercise in flash defrosting. Spontaneous microwaves rather than thaws... - Kirkus Reviews