Heat the butter in a small saucepan until melted, then brush all over the tortillas. Stir together the sugar and cinnamon in a small bowl, then sprinkle over the tortillas until well coated.
Cut the coated tortillas into equal triangles or strips and place on a baking sheet. Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 7–10 minutes until crisp.
Serve the tortilla chips with scoops of vanilla ice cream and fresh fruit.