Step 1: Make the Batter

1. In a large mixing bowl, whisk together the flour, baking powder, baking soda, and salt.
2. Pour in the beer and stir until the mixture is smooth and lump-free.
3. Cover the bowl and let the batter rest for one hour. This step allows the carbonation in the beer to activate for a better texture.

Step 2: Add the Egg

1. After resting, crack in the egg and whisk until the batter is smooth and slightly bubbly.
2. The batter should be thick enough to coat the mozzarella sticks but not so thick that it becomes clumpy.

Step 3: Coat the Mozzarella Sticks

1. Take each mozzarella stick and dip it into the batter, making sure it is fully coated.
2. Let any excess batter drip off before frying.
3. To prevent sticking, place the battered sticks on a parchment-lined plate before frying.

Step 4: Heat the Oil

1. Pour enough oil into a deep pot to submerge the mozzarella sticks.
2. Heat the oil to 350°F (175°C). A kitchen thermometer helps ensure accuracy.
3. If you don’t have a thermometer, drop a bit of batter into the oil. If it sizzles and rises to the top, the oil is ready.

Step 5: Fry the Mozzarella Sticks

1. Carefully place a few mozzarella sticks into the hot oil at a time.
2. Fry for about three minutes or until they are golden brown and crispy.
3. Use a slotted spoon to remove them and place them on a paper towel-lined plate to absorb excess oil.

Step 6: Serve Immediately

Mozzarella sticks are best enjoyed fresh while the cheese is hot and gooey inside. Serve with your favorite dipping sauces.