In a bowl, mix together the flour, milk, eggs, butter, sugar and salt.
Whisk vigorously until the batter is completely smooth.
Let the mixture rest while heating up the pan.
At medium heat, grease the skillet with the cooking oil.
Scoop a portion of the mixture into the skillet to cook the crêpe, flipping it over with a spatula to each side after 1-2 minutes. Remove from skillet when golden brown.
Repeat with the remaining mixture to make the rest of the crêpes (should be 4-6 crêpes in total).