Gather and measure all ingredients to streamline the process.

In a small bowl, combine the warm buttermilk (about 110°F) with the active dry yeast. Stir in 1 tablespoon of the brown sugar and let sit for 5-7 minutes until foamy.

In a large mixing bowl, whisk together the bread flour, remaining sugar, salt, and cinnamon.

In a separate bowl, mix the melted butter, beaten eggs, the foamed yeast mixture, and vanilla extract.

Gradually pour the wet ingredients into the dry ingredients, stirring until the dough starts to come together. Knead for about 5 minutes until smooth.

Cover the dough with a kitchen towel or plastic wrap in a warm area and let it rise for about 1 hour or until doubled in size.

Punch down the risen dough to release air. Roll it out on a floured surface to about 1-inch thick and cut out donut shapes using a donut cutter or two round cookie cutters.

Heat canola or vegetable oil in a deep pot to 350°F. Fry a few donuts at a time for 2-3 minutes on each side until golden brown. Drain on a paper towel-lined plate.

While the donuts cool slightly, mix the powdered sugar, browned butter, vanilla extract, and milk in a bowl until smooth. Dip the warm donuts into the glaze, letting excess drip off.

Serve the donuts warm and enjoy every bite!