Japan's Mister Donut doesn't seem to be in any danger of running out of delicious doughnut ideas. Just recently we've seen them release luxury Uji matcha, Pokemon, and mochi cream daifuku doughnuts.

This time the doughnut chain will be bringing back a popular release from last year, upgrading their sweet potato doughnuts with some new flavors.

On top of the dough used in the original doughnuts, which was made from anno imo, an orange sweet potato from Kagoshima with a particularly sweet honey-like flavor, the doughnuts also contain beni haruka imo powder, which comes from a swee potato with purple-red skin and a higher sugar content. Each of the five doughnuts in the lineup presents a different way to enjoy Japanese sweet potatoes.

Plain

A basic sweet potato-flavored doughnut using the above dough and powder with no extra frillas.

Beni imo

The sweet potato doughnut topped with beni imo (a purple sweet potato popular in Okinawa) glaze and sesame seeds.

Daigaku imo

"University Potatoes" (daigaku imo) are candied sweet potatoes, and take their name from being a popular snack with University students looking to save money but get a calorie-dense snack to help them power through the day. This doughnut has a sweet saucy glaze and sesame seed topping, much like the snack it's based on.

Sweet potato

Topped with sweet potato cream and sesame seeds.

Imo kenpi

Imo kenpi are fried strips of sweet potato coated with sugar, so this doughnut is coated with glaze and then broken up pieces of imo kenpi.

The doughnuts will be available at Mister Donut in Japan from September 4th until the middle of November.