Preheat the oven to 425°F (220°C). Line a baking sheet with parchment paper or lightly grease it so the potatoes won’t stick.

Wash and scrub the sweet potatoes. Leave the skins on for extra texture and nutrients. Cut each potato into 1-inch wedges or cubes, aiming for uniform pieces so they roast evenly.

In a large bowl, whisk together the honey, olive oil, kosher salt, black pepper, and ground cinnamon (if using). Stir in the lemon zest and half of the thyme leaves.

Add the sweet potato pieces to the bowl and toss gently until every piece is well coated in the honey mixture. Spread the potatoes in a single layer on the prepared baking sheet with some space between pieces to encourage browning.

Roast in the preheated oven for 20–25 minutes, flipping once halfway through. Roast until the potatoes are tender when pierced with a fork and edges are caramelized and lightly browned.

In the final 2 minutes of roasting, dot the potatoes with small pieces of butter if using, then return to the oven just long enough for the butter to melt and gloss the potatoes.

Remove from the oven and let them rest for 2–3 minutes. Sprinkle with the remaining fresh thyme and an extra pinch of lemon zest before serving to lift the flavors.

Serve warm as a side dish with roasted meats, grilled vegetables, or enjoy them as a cozy vegetarian main with a dollop of Greek yogurt or a handful of toasted nuts.