Place top oven rack in center position and pre-heat oven to 400°F.
Add sliced red beets and Brussels sprouts to a medium bowl and toss with two tablespoons olive oil and one teaspoon garlic powder.
Arrange beets and Brussels sprouts on a rimmed baking sheet lined with parchment paper or a Silpat™ baking mat in a single layer without overcrowding.
Add red onion quarters and brush with remaining olive oil and sprinkle with remaining garlic powder
Add fresh thyme sprigs to baking sheet. Sprinkle vegetables with pink Himalayan sea salt, and black pepper. Place in pre-heated oven for 25-30 minutes or until Brussels sprouts are golden brown and other vegetables are fork tender.
Remove baking sheet from oven and cool slightly before serving. Enjoy!