Preheat the oven to 400F and line a large baking sheet with parchment paper.
Add the halved potatoes to the parchment paper lined baking sheet and season with olive oil, salt and pepper and toss to combine. Place all of the potatoes cut-side down spread out on the baking sheet.
Bake the potatoes for 20 minutes.
While the potatoes bake, blanch the asparagus. Bring a large pot of water to a boil and once boiling add the asparagus stalks, cook for 2 minutes (thin asparagus) to 4 minutes (thick asparagus) or until just tender. Drain and rinse under cold water or put in an ice bath for 30 seconds-1 minute and then set aside and pat dry.
After the potatoes have been in the oven for 20 minutes, remove from the oven and nestle the cod filets in between the potatoes. Season the top of each cod fillet generously with salt and pepper and drizzle each filet with 1 tsp olive oil. Top each cod filet with 1-2 slices of lemon.
Put the baking sheet back in the oven and bake for an additional 10-12 minutes or until the cod flakes easily with a fork or is done to your liking (or an internal temperature of 135F is reached).
Let the cod and potatoes rest for a few minutes while you prepare the asparagus. Add the cooked asparagus to a large bowl and gently toss with the fresh chopped dill, fresh chopped parsley and 2-3 tablespoons of ladolemeno.
Serve the cod and potatoes with a side of the asparagus - drizzle some of the ladelemeno over the cod as well if desired.