Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
In a medium bowl, toss the halved baby potatoes with half of the olive oil, a pinch of salt, and a pinch of pepper.
Spread the potatoes onto the baking sheet and roast for 10 minutes to give them a head start.
While the potatoes are roasting, finely chop the rosemary and thyme and mince the garlic clove.
In a small bowl, whisk together the remaining olive oil, garlic, rosemary, and thyme.
Pat the chicken thighs dry with a paper towel and coat them thoroughly with the herb-oil mixture, seasoning with the remaining salt and pepper.
Remove the baking sheet from the oven and move the potatoes to one side; add the chicken thighs and trimmed asparagus spears to the empty space.
Thinly slice the lemon and place the rounds directly on top of the chicken and asparagus for maximum flavor infusion.
Return the sheet to the oven and roast for an additional 20-25 minutes until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender.
Let the chicken rest for 5 minutes before serving to allow the juices to redistribute for a moist and tender result.