Preheat the oven to 375 degrees F (190 degrees C). Lightly coat an 11x7-inch baking dish with nonstick cooking spray.

Place potatoes in a single layer in the prepared dish, and top with onion. In a small bowl, combine melted butter, honey, mustard, salt, and pepper; drizzle over potatoes and onion.

Bake in the preheated oven for 35 minutes or until tender, stirring halfway through the cooking time.