Blessed be expansion, the Holy Donut is coming to Scarborough.

After four years of selling potato-dough doughnuts in Portland, sometimes selling out by midday, Holy Donut owner Leigh Kellis has decided to open a new location on Route 1 in Scarborough, near the Haigis Parkway. The new Holy Donut will be located in a building that had housed a Tim Hortons coffee shop. It should be open by March, Kellis said Wednesday.

The location, at 3,000 square feet, is about double the size of each of the Portland Holy Donut locations, on Park Avenue near Deering Oaks and on Exchange Street in the Old Port. The Scarborough location, besides being a retail outlet, will be used to make all the dough and glaze each day for the three stores. Those ingredients will be delivered to the other shops, where doughnuts will still be made on site, Kellis said.

The former Tim Hortons has been vacant for about a year. The Canadian chain has closed at least a half dozen of its Maine shops over the last three years.

The Holy Donut quickly gained a loyal following after opening four years ago, with some 20 creative flavors ranging from pomegranate and dark chocolate sea salt to bacon cheddar-filled and Allen’s Coffee Brandy. Kellis says she’s not sure if the increased size of the new Scarborough location will lead to Holy Donut making more kinds of doughnuts.

Kellis, a Portland native, had worked in hotels for about 10 years before starting to make doughnuts in her home kitchen in 2011 and selling them to stores and restaurants. She was working at Maine-based Otto pizza restaurants at the time.

Kellis opened the first Holy Donut on Park Avenue in March 2012, and the Exchange Street location in October 2014. She said Wednesday she’d been eying a possible Scarborough location for about two years. When she first saw the former Tim Hortons, she thought it was too far south on Route 1. But the building’s size, amenities and the heavy traffic on that part of Route 1 convinced her to sign a lease and start the conversion.

“We do a good business at our other locations, and this felt like the logical next step,” Kellis said.

Holy Donut earned national attention. The New York Times, Bon Appetit and Elle Magazine are among the publications that have written about it.

Holy Donut shops close when the day’s doughnuts sell out. Sometimes that’s as early as midday. Kellis said people often ask her to ship doughnuts around the country, but she won’t.

She doesn’t want people to have to eat day-old doughnuts.