Preheat oven to 450 degrees.
Cut asparagus in half, adding to a 9x13 glass baking dish. Drizzle with 1 tbsp olive oil, salt & pepper.
Coat the chicken breasts with the remaining 1 tbsp of olive oil, as well as a bit of salt & pepper.
Cut 1 lemon into thin slices. Add the slices on top of the chicken. Squeeze juice from the remaining 1/2 lemon evenly over the entire pan of chicken & asparagus.
Place the pan in the oven and bake for 40 minutes. or until chicken is cooked all the way through (it should reach 165 degrees at it's thickest point).
Optional: When you have 20 minutes left in baking time, take the pan chicken & asparagus out, and sprinkle entire pan with parmesan. Place back in the oven for the remaining 20 minutes.
Serve the chicken and asparagus together, along with a side salad for a well-rounded meal.