Preheat your oven to 425°F (220°C) if you prefer a lightly roasted finish; otherwise, you can finish on the stovetop to save time. Line a baking sheet with parchment for easy cleanup.
In a large bowl, toss the cubed sweet potatoes with olive oil, salt, and pepper until evenly coated. This helps them crisp and caramelize.
Spread the potatoes in a single layer on the prepared sheet. Roast for 15–20 minutes, flipping halfway, until the edges are golden and the centers are tender when pierced with a fork.
While the potatoes roast, melt the butter in a medium skillet over medium heat. Let it cook, swirling occasionally, until it turns a nutty amber color and smells deeply toasty—this is your browned butter moment.
Add the chopped sage to the browned butter and give it a quick stir to bloom the herb in the hot fat, about 30–45 seconds. The sage will become crisp and release its aroma.
If you roasted the potatoes, remove them from the oven and transfer to a warm serving bowl. Drizzle the browned butter with sage over the potatoes and toss gently to coat.
If you’re finishing on the stovetop, add the roasted potatoes to the skillet with the browned butter and toss to coat. Allow them to sit a minute to soak up the flavor before turning once more for an even coat.
Taste and adjust with a pinch more salt or a squeeze of lemon juice for brightness. A light drizzle of balsamic glaze can also enhance the sweetness and add a glossy finish.
Serve warm as a comforting side dish or a centerpiece alongside roasted chicken, turkey, or a hearty vegetable main. The potatoes are best on the day they’re made but can be stored in the fridge for up to 2 days and reheated gently.