Trim the ends from the Brussels sprouts and remove any wilted leaves. Cut vertically into 5 or 6 slices. Add to a bowl and toss with 2 tablespoons olive oil.
Spread on a rimmed baking sheet, sprinkle with salt and pepper, and roast for 20 minutes.
Meanwhile, core apple and slice thinly. Set aside. Chop the pecans into small pieces, if needed.
To make the dressing, whisk together maple syrup, cider vinegar, dijon, and salt until blended. While whisking, pour in the olive oil, then continue to whisk until dressing is emulsified and looks thick and opaque. Add more olive oil to thin further if desired.
Once the sprouts are done, add to a large bowl or serving dish. Add the apples, cranberries, and pecans. Drizzle about 2/3 of the dressing over the sprouts and then toss everything together to coat.
Serve immediately, at room temperature, or chilled, with remaining dressing for serving.