Combine flour, sugar (if using), and salt in a bowl.

In a separate bowl, lightly beat the egg.

Add milk and oil to the egg mixture.

Pour the wet ingredients into the dry ingredients and stir until smooth.

Gently fold in the thinly sliced apples.

Heat a lightly greased griddle or frying pan over medium heat.

Pour 1/2 cup of batter onto the hot griddle for each pancake.

Spread the batter to form a 5-inch circle.

Cook until bubbles form on the surface and the edges start to set.

Flip the pancake and cook the second side until golden brown and the apples are tender.

Sprinkle with confectioners' sugar, if desired.

Serve immediately.