Gather and measure all ingredients. Take the egg and milk out of the refrigerator 15–20 minutes before starting so they reach room temperature, and melt butter now if using instead of oil.
Crack the egg into a medium mixing bowl and beat vigorously with a whisk or hand mixer for 1–2 minutes until light, frothy, and pale yellow.
Pour the milk and vegetable oil (or cooled melted butter) into the bowl with the beaten egg and whisk together until smooth and uniform.
In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt for about 30 seconds until evenly combined with no lumps.
Pour the wet ingredients into the dry ingredients and gently stir with a rubber spatula just until the flour is moistened — stop as soon as no dry flour remains, leaving a few lumps in the batter.
Let the batter rest undisturbed for 5–10 minutes at room temperature while you preheat the griddle; this hydrates the flour and activates the baking powder for fluffier pancakes.
Heat a nonstick griddle or skillet over medium-high heat (375°F/190°C for electric griddles) for 3–5 minutes, then lightly brush with oil or coat with cooking spray.
Use a 1/4 cup measuring cup to pour batter onto the hot griddle, spacing pancakes about 2 inches apart and letting the batter spread naturally into circles.
Cook undisturbed for 2–3 minutes until bubbles form and pop across the surface and the edges look dry and slightly set.
Slide a spatula fully under each pancake and flip confidently in one smooth motion; cook the second side for 1–2 minutes until golden brown and the center springs back when gently pressed.
Transfer cooked pancakes to a plate covered loosely with foil, or keep in a 200°F (95°C) oven while finishing the remaining batter; serve hot with butter, maple syrup, and desired toppings.