Preheat the oven to 425 degrees. Line a large baking sheet with parchment paper or lightly grease it.
Pat the baby carrots dry with paper towels, then add them to a large bowl.
In a small bowl, whisk together the olive oil, melted butter, honey, Dijon mustard, salt, black pepper, and thyme.
Pour the honey mixture over the carrots and toss until evenly coated.
Spread the carrots in a single layer on the prepared baking sheet, leaving some space between them.
Roast for 25 to 30 minutes, tossing once halfway through, until the carrots are tender and caramelized around the edges.
Taste and season with additional salt or pepper if needed before serving.