Pat the plaice fillets thoroughly dry with paper towels to ensure a crisp sear, then season both sides evenly with sea salt and black pepper.
Heat the extra virgin olive oil in a large non-stick skillet over medium-high heat until it begins to shimmer.
Carefully place the plaice fillets in the skillet and sear for 2 to 3 minutes per side until the edges are golden and the fish flakes easily with a fork.
Transfer the cooked fish to a warm plate and set aside.
In the same skillet, add the minced garlic and sauté for 30 seconds until fragrant, being careful not to let it burn.
Add the cauliflower rice and asparagus spears to the skillet, sautéing for 4 to 5 minutes until the vegetables are tender-crisp.
Whisk in the fresh lemon juice, chopped dill, and capers into the vegetable mixture, tossing well to combine and deglaze the pan.
Serve the pan-seared plaice over the bed of lemon-dill vegetables, drizzling any remaining pan juices over the top.