Toss potato wedges, fennel, onion, garlic, sage, olive oil, and salt and pepper in a bowl. Make sure everything is coated well with the olive oil. Spread it all out onto a baking sheet and roast at 425 degrees until golden and crisp, about 35-45 minutes, tossing halfway through. Once finished, season with more salt and drizzle with a little more olive oil, if desired.