Preheat your oven to 400°F (200°C).
In a large mixing bowl, combine the olive oil, honey, minced garlic, salt, black pepper, and thyme. Whisk until well blended.
Add the cleaned mushrooms to the bowl and toss until they are evenly coated with the honey-garlic mixture.
Spread the mushrooms in a single layer on a baking sheet lined with parchment paper.
Roast in the preheated oven for 20-25 minutes, or until the mushrooms are tender and caramelized, stirring halfway through for even cooking.
If using, drizzle the balsamic vinegar over the mushrooms during the last 5 minutes of roasting.
Remove from the oven and let cool for a few minutes before serving.