Season the chicken strips with sea salt and black pepper. Dredge in all-purpose flour until coated. Heat olive oil in a skillet and sauté chicken for 3-4 minutes on each side until golden brown. Remove and set aside.

In the same skillet, add more olive oil if needed, then sauté thick-sliced mushrooms and diced onion for 7-8 minutes until softened and golden. Add minced garlic in the last minute, stirring continuously.

Reduce heat to medium and add butter until melted. Whisk in flour to create a roux, cooking for 1-2 minutes. Gradually add chicken broth while whisking. Mix in lemon juice and half and half, simmering until creamy.

Layer sautéed mushrooms and onions over the chicken in a casserole dish. Pour sauce on top, cover with foil, and bake at 350°F (175°C) for 45 minutes, removing foil in the last 5-10 minutes.

Let rest for a few minutes after baking. Garnish with fresh parsley or thyme before serving.