Neighbours rushed to help the 78-year-old, who made a desperate bid to escape as a dessert shop next door to her home was set on fire.
The woman managed to get out safely but neighbouring Sweet Treat was completely gutted by the blaze.
Police have launched an investigation into the attack on on Lord Street, Palfrey, which is being treated as arson.
Witnesses described seeing a group of men set fire to the shop minutes after it closed at 10pm on Saturday.
A petrol bomb was reportedly thrown through the window, while a BMW outside was also torched.
A resident, who did not want to be named, told how the elderly woman was rescued from the house next door.
She said: "Luckily, one of the neighbours saw the fire and started knocking on the door, they saw her from the window.
"They came across the road, banged on the glass and took her out."
Police said the suspects had been spotted on CCTV running away from the shop towards Queen Mary Street and have called for anyone with information to come forward.