In a mixing bowl, whisk together the sifted all-purpose flour, granulated sugar, baking powder, and salt. This ensures that the dry ingredients are well combined and helps to aerate the flour.

In a separate bowl, combine the milk, beaten egg, and vanilla extract. Mix until well combined.

Gradually add the wet ingredients to the dry ingredients, whisking until you achieve a smooth batter. Avoid overmixing to keep the batter light and airy.

In a deep fryer or large pot, heat the vegetable oil to 350°F (175°C). Use a thermometer to ensure the oil is at the right temperature for frying.

If the oil is not hot enough, the batter will absorb too much oil and become greasy. If it's too hot, the batter will burn before the Oreos are cooked through.

Dip each Oreo into the batter, ensuring it is fully coated. Allow any excess batter to drip off.

Carefully place the battered Oreos into the hot oil, a few at a time, to avoid overcrowding. Fry for about 2-3 minutes on each side, or until golden brown.

Use a slotted spoon to remove the fried Oreos from the oil and place them on a plate lined with paper towels to absorb excess oil.

Once all the Oreos are fried, dust them generously with powdered sugar while they are still warm. This adds sweetness and a beautiful presentation.

Serve immediately while hot for the best texture and flavor.