Heat butter in a large heavy skillet over medium-high heat. Add apples and cook, stirring, for about 5 minutes, or until lightly browned.
Add maple syrup and bring to a boil. Reduce heat and cook for 5 to 7 minutes, or until apples are tender and caramelized.
To assemble crêpes, place crêpes, nicest side down, on a work surface. Divide caramelized apple mixture among crêpes. Roll up and place on a parchment-lined baking sheet.
Before serving, warm crêpes in a preheated 350°F (180°C) oven for 5 to 10 minutes.