Combine flour and salt in a large bowl; gradually whisk in milk. Add eggs and maple syrup and mix until batter is smooth. Spoon into a piping bag.
Heat a poffertjes pan over high heat and lightly grease indentations. Fill the holes 3/4 full with batter in the piping bag and cook over high heat until golden brown; turn them over with a fork and cook the other side until golden brown.