Preheat oven to 475°F.
Toss the sweet potatoes with olive oil, salt and pepper and spread on a cookie sheet in a single layer.
Roast in the top half of the oven for 10 minutes, then flip and roast for another 5 minutes.
While the potatoes are roasting, melt the butter in a skillet over medium heat until it starts to brown, about 1 minute.
Add the apples in a single layer and brown on both sides, about 90 seconds per side.
Then add the chopped sage and stir until wilted, about another 30 seconds.
Remove from heat and fold in the lemon juice and maple syrup. Scrape them into a serving bowl with a spatula and gently combine in the roasted potatoes.