Preheat oven to 375 degrees. Toss Brussels sprouts and grapes with olive oil, balsamic vinegar, thyme, salt, and pepper. Place on a baking sheet in a single layer with the cut side of the Brussels sprouts facing down. Roast for 25-30 minutes, or until the Brussels sprouts are tender and the cut-side is turning a dark golden brown. Sprinkle the slivered almonds on top and place back in oven for an additional 5 minutes. Remove from oven, toss, transfer to a serving bowl, and enjoy