Preheat your oven to 400°F (200°C).
In a large bowl, combine the diced apples and sliced carrots.
In a separate bowl, whisk together Dijon mustard, maple syrup, olive oil, salt, and pepper.
Pour the dressing over the apples and carrots, mixing until well-coated.
Spread the coated mixture onto a baking sheet lined with parchment paper.
Roast in the preheated oven for about 25-30 minutes, stirring halfway through.
Taste and adjust seasoning if necessary, then garnish with fresh rosemary.
Serve warm as a delightful side or main dish.