Preheat oven to 425°F and line a cooking tray with parchment paper.
Cut washed and trimmed Brussels sprouts in half and season with salt and pepper.
Place cut side down on parchment paper and bake for 15-20 minutes. Brussels sprouts should be tender and golden brown.
While the Brussels sprouts are cooking, combine the mustard, applesauce, lemon juice, maple syrup, and thyme in a large bowl. Whisk to combine and season with salt and pepper.
Remove the Brussels sprouts from the oven and let them cool slightly. Place the Brussels sprouts in the bowl with dressing along with the diced apples and walnuts.
Toss to combine and serve warm. ENJOY!