Nutty, slightly bitter tahini (sesame seed paste) keeps these little pastries from getting too sweet.
Preheat oven to 350°. On work surface, unroll dough sheet, gently pinching seams to seal. Spread chocolate-hazelnut spread to edges of dough. Drizzle with tahini; sprinkle with chocolate chips. Starting at a short end, roll into a log. Using a serrated knife, cut log crosswise into 8 rounds. Brush 8 muffin tin cups with butter. Add rounds; brush with remaining butter. Sprinkle with sesame seeds. Bake until golden, 15 to 17 minutes.