Set your oven to 425 °F. Prepare a large rimmed baking sheet (skip the foil or parchment—direct contact = crispier potatoes).
In a large white bowl, toss the halved potatoes with olive oil, salt, pepper, and chopped thyme until evenly coated.
Spread the potatoes cut-side down on the baking sheet in a single layer, leaving space between pieces to allow for proper roasting.
Roast for 15 minutes to start developing that golden crust.
Scatter the thick-chopped garlic over the potatoes and gently flip them with a spatula to expose the other side and mix in the garlic flavor.
Return the tray to the oven and roast for another 20 minutes, until crisp and deeply golden outside, and creamy-tender inside.
Taste, adjust seasoning if needed, and serve immediately.