"It'll just be as though you went to Sister Pie and suddenly you could get a sandwich," she said.

Ludwinski's business has long since run out of room at its 950-square-foot Kercheval shop, where customers can buy baked goods with an eccentric touch, such as shortbread with lavender and grapefruit, buckwheat chocolate chip cookies and salted maple pie. It can seat around 15 people indoors and maybe 10 outdoors, she said.

In the new space, the head baker also wants to build out a grocery area with packaged salads and sandwiches; basic goods it is already buying from vendors, such as potatoes, milk, butter and eggs; and maybe a couple of heat-at-home pot pies.

"Not only could someone coming to a class use some of those items to make food out of the cookbook or whatever," Ludwinski said, referencing the recipe collection she released in October titled Sister Pie: The Recipes and Stories of a Big-hearted Bakery in Detroit. "But people who live around the corner could get (milk or butter).

"Hopefully that would allow us to be even more sustainable. … We could start making things like cereals, or we can use even more of our ingredients to push into the grocery section of our store. We can make use of everything we have here in the bakery even more, because we'll have different paths for us to grow. Kind of an effort to use all of our resources to our potential."

The new location would also house two classrooms so Sister Pie could expand its cooking classes, which are generally more profitable than baked goods sales and could help it offset costs as Ludwinski considers ways to keep products affordable. The waiting list for a spring class series is at least 100 people long, she said. Classes listed on Sister Pie's website cost $80.

Ludwinski plans to offer least 24 classes a month, up from the current three to four. They could include anything from multiday workshops and custom events to classes for kids and older residents, and free community classes.

The fourth component of the expansion plan is offices for Sister Pie's administrative staff.

Sister Pie has not yet signed a lease for the Mack Avenue building, but has a letter of intent with the owner. The owner, through Ludwinski, declined to be named or interviewed. Mack 1920 LLC, the owning entity, purchased the building in 2014 for $22,200 from the Wayne County treasurer, according to city records. Mack 1920 is registered with the state to Detroit-based Counsel Matters PLLC.