Preheat oven to 425°F (220°C).
Pat chicken thighs dry with paper towels so the skin crisps up in the oven.
Make the garlic herb rub: Mix garlic, olive oil, rosemary, thyme, paprika, salt, and pepper in a bowl.
Season the chicken: Rub the mixture all over the thighs, making sure some goes under the skin.
Arrange on a tray: Place the thighs skin-side up on a baking sheet or skillet. Add lemon slices if using.
Roast in the oven for 35–40 minutes, until the skin is golden and crispy and the inside reaches 165°F (74°C).
Rest and serve: Let the chicken sit for 5 minutes before serving so the juices stay inside.