Preheat your oven to 425°F (220°C) and line a large sheet pan with parchment paper.
Halve the baby potatoes and trim the woody ends off the asparagus spears.
Pat the chicken breast completely dry with a paper towel to ensure the skin or surface gets maximum crispiness.
In a small bowl, whisk together the extra virgin olive oil, dried oregano, garlic powder, sea salt, and black pepper.
Place the chicken breast and halved potatoes on the sheet pan, then drizzle with two-thirds of the herb oil mixture, tossing the potatoes to coat evenly.
Roast in the oven for 15 minutes.
Remove the pan and add the asparagus and lemon slices, drizzling them with the remaining herb oil.
Return the pan to the oven and roast for another 10-12 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are golden brown.
Garnish with fresh rosemary leaves and serve immediately with the roasted lemon slices for squeezing.