Add the bananas to a blender and blend until completely smooth. You want a lump-free puree so it incorporates cleanly into your dough and sauces.

In a large nonstick pan, melt the butter over medium heat. Stir in the banana puree and brown sugar.

Cook for about 10–15 minutes, stirring every minute or so. The mixture will start pale yellow and gradually turn deep golden brown. You're looking for a thick, jammy texture—something between banana jam and apple butter.

Once it’s thick, glossy, and reduced, spread it onto a large plate to cool quickly. Let it come to room temperature before using.

In a small bowl, combine the warm milk, yeast, and 1 teaspoon of granulated sugar. Let sit for 5–10 minutes until foamy and bubbly on top.

In the bowl of a stand mixer fitted with the dough hook, whisk together the flour, dry milk powder, and salt.

Add the remaining granulated sugar, eggs, banana reduction, and activated yeast mixture to the dry ingredients.

Knead on low speed for 4 minutes, just until the dough starts coming together.

Add the softened butter one tablespoon at a time, allowing each piece to fully incorporate before adding the next. This should take about 2–3 minutes total.

Once all the butter is in, knead on medium speed for another 6–8 minutes. The dough should be soft, smooth, elastic, and slightly sticky—but not wet.

If it still feels too sticky, let it rest for 5 minutes, then knead 1 more minute to allow the flour to absorb the butter fully.

Transfer the dough to a greased bowl, cover tightly, and refrigerate for 8–12 hours. Overnight is best so it’s cold and easy to handle the next day.

While the dough chills, make the banana caramel sauce so it has time to cool.

In a medium, heavy-bottomed saucepan, combine the sugar, water, and corn syrup. Stir just enough to moisten the sugar, then stop stirring.

Set the pan over medium heat and cook undisturbed for 5–10 minutes. The sugar will dissolve, bubble, then darken to a rich amber color—like honey or a shiny copper penny.

Meanwhile, warm the heavy cream in the microwave for about 1 minute.

As soon as the caramel reaches a deep amber color, remove it from heat and slowly pour in the warm cream. It’ll bubble up dramatically, so go slow and whisk as you pour.

Once the bubbling settles, whisk until smooth. Stir in vanilla, salt, and banana reduction.

If needed, return the pan to low heat for a minute or two to fully combine.

Let cool slightly, then transfer to a heat-safe jar. It will thicken as it cools. Store leftovers in the fridge for up to a week and warm gently before using.

The next day, turn the cold dough onto a floured surface and roll it to ½-inch thickness. Use enough flour to prevent sticking but not so much that it dries out the dough.

Use a donut cutter to cut out donuts. For the scraps, twist them into crullers instead of re-rolling—this dough doesn’t like being worked twice.

Place the cut donuts on greased parchment paper, cover loosely, and let rise at room temperature for about 30 minutes, or until visibly puffy.

While they rise, heat your oil to 350°F in a large heavy pot or deep fryer.

Fry the donuts in batches, about 90 seconds per side, until puffed and light golden brown.

Use chopsticks or tongs to flip them gently. Avoid overcrowding the pot—this helps the oil temperature stay consistent.

Drain the donuts on a paper towel-lined wire rack. Let cool slightly while you make the glaze.

In a large bowl, whisk together the powdered sugar, salt, vanilla, melted butter, hot water, and banana caramel until smooth and pourable.

If the glaze is too thick, microwave it for 10 seconds to loosen it up.

Dip just the tops of the donuts into the glaze and let the excess drip off. Place them back on the wire rack to set completely.