Prepare the ingredients by coring the apples and chopping them into ½” cubes, slicing the carrots into ¼” thick pieces, dicing the onion, and finely chopping the garlic.
Make the glaze by whisking together olive oil, maple syrup, dijon mustard, salt, black pepper, and thyme in a large bowl.
Combine the chopped carrots, apples, onions, and garlic with the glaze, tossing until well coated.
Preheat the oven to 425°F (220°C) and spread the mixture evenly on a baking sheet. Roast for about 15 minutes, flipping halfway through.
Continue roasting for another 10 to 15 minutes until the carrots are tender and the glaze has caramelized.