Preheat the oven to 400 degrees F. Coat a sheet pan with cooking spray.
Place the olive oil, butter, garlic, salt, pepper and thyme in a large bowl. Whisk to combine.
Add the carrots and potatoes to the bowl and toss to coat.
Pour the vegetables onto the sheet pan and spread into a single layer.
Cook for 30-40 minutes or until potatoes and carrots are tender.
Sprinkle with parsley, then serve immediately.
