Combine 2 tablespoons of oil in a small mixing bowl with 1 tablespoon fresh thyme, both types of paprika, cinnamon, onion powder, garlic powder, and sugar. Massage into chicken thighs, including under the skin. Cover and marinate in the refrigerator for at least 4 hours or overnight.
Preheat oven to 425°F. Arrange chicken thighs skin-side up on a foil-lined baking sheet. Roast until internal temperature reaches 160°F, about 20-25 minutes.
Heat remaining 2 tablespoons of oil in a skillet over medium-high heat. Add garlic and thyme to infuse oil. Sear roasted thighs for 2-3 minutes per side until skin is golden and crispy. Serve immediately.
Notes
For maximum flavor, marinate overnight. Use a meat thermometer to ensure doneness. Clean-up is easier with foil on the baking sheet.