In a large mixing bowl, whisk together the flour, granulated sugar, baking powder, salt, and ground cinnamon until well combined.

In a separate bowl, mix the buttermilk, egg, and melted butter until smooth.

Pour the wet ingredients into the dry ingredients and stir until just combined. The dough will be slightly sticky.

Turn the dough out onto a floured surface and gently knead it a few times until it comes together. Pat it into a rectangle about 1/2 inch thick.

Cut the dough into squares or rectangles, about 2 inches wide.

In a deep skillet or pot, heat about 2 inches of vegetable oil over medium heat until it reaches 350°F.

Carefully drop a few pieces of dough into the hot oil, frying them in batches to avoid overcrowding. Fry for about 2-3 minutes on each side or until golden brown.

Use a slotted spoon to remove the beignets from the oil and place them on a paper towel-lined plate to drain excess oil.

While still warm, dust generously with powdered sugar before serving.