1. Prepare the Wet Ingredients

• In a small mixing bowl, combine the milk, vanilla extract, and apple cider vinegar. Let it sit for 5 minutes to allow the vinegar to sour the milk slightly, creating a buttermilk-like effect.

2. Mix Butter and Sugar

• In a large mixing bowl, whisk together the softened butter and 1/2 cup sugar until the mixture is soft and fluffy. This step ensures the donuts are light and tender.

3. Combine the Dry Ingredients

• In a separate bowl, sift together the flour, baking soda, and salt. This helps prevent lumps and ensures an even rise.

4. Combine Wet and Dry Ingredients

• Gradually add the dry ingredients to the butter-sugar mixture, alternating with the milk-vinegar mixture. Stir gently until a soft dough forms, being careful not to overmix.

5. Roll Out the Dough

• On a lightly floured surface, roll out the dough to about 1/2-inch (1.25 cm) thickness. Using a donut or cookie cutter, cut out donut shapes and set aside the donut holes if you’d like to fry them as well.

6. Rest the Dough

• Place the cut donuts on a tray and cover them with a kitchen towel. Let the dough rest for 10 minutes to help the donuts puff up better during frying.

7. Heat the Oil

• In a heavy-bottomed pan or wok, heat about 1-2 inches of oil over medium heat until it reaches 350°F (180°C). Use a thermometer if possible to maintain a consistent temperature.

8. Fry the Donuts

• Carefully place a few donuts into the hot oil, frying in batches to avoid overcrowding. Fry each side for about 1-2 minutes or until golden brown.
• Use a slotted spoon to remove the donuts and place them on a paper towel-lined plate to drain excess oil.

9. Coat in Sugar and Serve

• While the donuts are still warm, roll them in the remaining 1/4 cup of sugar to coat.
• Serve immediately, either plain or with a glass of milk.