I tried popular flavors at one of the most famous doughnut shops in Maine. I'd travel miles just for the blueberry glazed.

The Holy Donut was dreamed up by single mother Leigh Kellis in her apartment kitchen.

The business has since grown into a local institution with five locations and now has even bigger dreams, largely thanks to the efforts of CEO and co-owner Jeff Buckwalter.

"I think a big part of our story is it's a wonderful American dream story. The family coming together and just figuring it out," he told Business Insider during a visit to The Holy Donut in August. "Also, within a community that has — I don't know that it doesn't exist outside Portland — but has a rising tides mentality. Everybody is willing to help everybody."

Buckwalter said that while the Park Avenue location is pretty busy, the busiest location is on Commercial Street in the heart of the Old Port.

Across all of its locations, he said they probably sell around six or seven million doughnuts each year, mostly during the summer at the height of tourism in Maine — and that he hopes to expand into shipping in order to sell even more nationwide.

"We are going to own the doughnut shipping space nationwide and we are going to be known as a very well-managed and scaled family company that now has a nationwide brand," Buckwalter said of his goals for The Holy Donut in the next five years.

I bought some of the chain's most popular doughnuts to see what all the fuss was about.

The doughnut was completely covered in large coconut flakes. As a huge fan of the Girl Scout cookie Samoas, I was interested to see if this flavor combination was similar.

One of the first things I noticed about this doughnut was its weight and size — it was heavier than doughnuts I've had in the past and I wondered if that was due to the inclusion of potatoes in The Holy Donut's recipes.

Bon Appetit reported in 2016 that the business credits "The Joy of Cooking" with giving founder Leigh Kellis the original idea for a potato doughnut.

Kellis also discovered that when she added riced potatoes to the recipe, the doughnuts came out fluffier and didn't dry out as quickly.

The coconut had a slightly sweet flavor that wasn't too overpowering, and the chocolate flavor also came through.

The cake part of the doughnut was thick without being too stodgy. It was distinctly different from other doughnuts I've tried.

It was also more filling and substantial, though I wasn't complaining about that considering this doughnut cost $5. You can also order a half-dozen of assorted donuts for $22, or a full dozen for $44.

The doughnuts I tried were given to me, free of charge, when I tasted them during my behind-the-scenes visit to The Holy Donut. However, I returned a few days later to purchase the same flavors — except the savory bacon and cheddar doughnut, which had sold out — so I could try them again.

Buckwalter told me this flavor is one of the most — if not the most — popular doughnuts The Holy Donut sells. It's a dark chocolate and sea salt base covered in a simple icing glaze.

The slightly salty flavor balanced out the sweetness of the chocolate doughnut and the light layer of glaze.

This doughnut was also slightly thinner than the coconut doughnut, which made it a touch easier to eat. I could have easily polished off one or even two of these doughnuts.

This doughnut costs $4.25, excluding tax, and is also available in a gluten-free version for $5.25.

After watching the bacon cheddar doughnuts being made right in front of me, I had to try one. It was a unique menu item that reminded me a little bit of a bacon, egg, and cheese sandwich back home.

Unlike most of the other doughnuts sold by The Holy Donut, the bacon cheddar doughnut doesn't have a hole and is made with plain dough stuffed with bacon and half-melted sharp cheddar cheese.

The plain doughnut encasing the ingredients was crispy and bread-like, allowing the flavors of the bacon and cheese to shine through.

My only criticism is that the dough was a touch dry. A simple pat of butter would have moistened it.

This could also have been an effect of the dough used to make these doughnuts, which were "second cuts" or put-back-together dough after previous doughnuts had been rolled out and cut.

"These are second cuts, they behave a little differently," Buckwalter said, adding they have a little more gluten than other doughnuts.

The smell of the blueberry glaze wafted throughout the doughnut shop throughout the morning I visited, which fell right at the peak of Maine's blueberry season.

The Holy Donut was offering four different seasonal blueberry flavors through Labor Day: blueberry glazed, blueberry lemon, blueberry cinnamon sugar, and holy cannoli blueberry.

"Maine, in the eastern part of our state, is famous for our little sweet, tart blueberries, so we do lean heavily into local," Buckwalter said.

"Our blueberries come from either Wyman's Farms or Passamaquoddy, a North American Native American tribe that is heavily into blueberries," he continued.

The doughnut reminded me slightly of a blueberry muffin, but it was much more flavorful and appetizing, thanks to the thick layer of blueberry glaze and the moist, cake-like doughnut.

This doughnut cost $4.50, excluding tax.

The emphasis on using local ingredients certainly paid off when it came to this doughnut — I've never had a more flavorful blueberry doughnut in my life.

Biting in, the doughnut was the perfect amount of fluffy and crispy, with a flavor that practically transported me to having blueberry pancakes for breakfast at my parents' house as a kid.

Though it's only available through Labor Day, this doughnut proved that sometimes seasonal flavors are simply worth the wait and the hours spent traveling to try it.