Its square shape is a bit of a departure from the more typical round, which has turned this doughnut into a social media sensation. The Dupont Circle go-to (which also serves a twist on Southern chicken and waffles) fills its most-popular doughnut with vanilla custard pastry cream, tops it with vanilla glaze and torches it for that signature caramel-flavored bruleed finish.

Like a mash-up of brown butter brickle ice cream and hazelnut biscotti, the Brown Butter Hazelnut Crunch doughnut at Union Square Donuts is crafted using a butter-based brioche dough (which gives it a light and airy, almost pastrylike texture, according to co-owner Josh Danoff). It’s topped with a butter glaze and sprinkled with toasted, crushed hazelnuts, and it's a perfect example of the globally inspired doughnuts at the Somerville store.

After creating churro-inspired treats for Cinco de Mayo, Pink Box Doughnuts (where pastry chefs bake for a staggering 18 hours each day) decided to offer them the entire year, not only in celebration of Mexico’s independence. Their long, glazed bar has a freshly fried and cinnamon-garnished churro sunk into the middle, and it is topped with a generous amount of creamy dulce de leche.

Housed in an old print shop on the back side of Indianapolis’ Fountain Square district, General American Donut Company is decorated with mid-century modern furniture, industrial finishes, and funky and pop culture accents. Like the candy of the same name, the raised Salt Caramel doughnut is a yeast doughnut frosted with housemade caramel and sprinkled with sea salt. (It’s perfect with the Stumptown Coffee they brew too.)