1. Prepare Your Workspace: Clear your kitchen counter. Lay out parchment paper or a cutting board for rolling the dough. Have a wire rack ready, placed over a baking sheet, to drain the fried beignets.

2. Whisk Dry Ingredients: In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, baking soda, and salt. Combine thoroughly.

3. Combine Wet Ingredients: In a separate medium bowl, lightly whisk the large egg. Pour in the buttermilk and vanilla extract. Whisk until just combined.

4. Mix Wet into Dry: Create a well in the center of the dry ingredients. Pour the wet mixture into the well. Using a wooden spoon or spatula, mix until just combined. Do not overmix; a few lumps are fine.

5. Chill the Dough (Optional but Recommended): Cover the bowl with plastic wrap. Refrigerate the dough for at least 30 minutes, or up to an hour. This helps firm the dough and relaxes the gluten.

6. Heat the Oil: Pour 6-8 cups of vegetable oil into a large, heavy-bottomed pot or Dutch oven. Attach a deep-fry thermometer. Heat over medium-high heat until it reaches 350-360°F (175-182°C).

7. Roll and Cut the Dough: Lightly flour your work surface. Turn the chilled dough out onto the floured surface. Gently pat or roll into a rectangle about 1/2 inch thick. Use a sharp knife or pizza cutter to cut into approximately 2-inch squares.

8. Fry the Beignets: Carefully drop 3-4 beignet squares into the hot oil at a time. Do not overcrowd. Fry for 1-2 minutes per side, until golden brown and puffed. They will float as they cook.

9. Drain and Dust: Use a slotted spoon or spider strainer to remove the beignets. Transfer to the prepared wire rack to drain excess oil.

10. Dust with Powdered Sugar: While still warm, liberally dust with powdered sugar using a sifter. Serve immediately.