In a small sauce pan over medium high heat, sauté shallot and garlic in olive oil for about 2 minutes. Add butter and stir until melted. Add chicken broth, basil, tarragon and lemon. Keep warm until ready to serve.
Heat a large oven safe pan over medium high heat. Season each side of cod fillets with salt and pepper. Add olive oil to hot pan and sear each side of each cod fillet, one minute each side. Place pan in oven and cook for about 5 minutes. This really depends on how thick your fillets are. Cook until opaque in the middle and just starting to flake.
Wilted Spinach & Mushrooms
Heat a large pan over medium high heat. Add olive oil, then mushrooms, sauté until browned about 4 minutes. Add garlic, spinach and red pepper flakes. Cook until spinach is wilted.
Place spinach and mushroom mixture in a mound on plate. Place fillet on top and spoon over shallot lemon sauce.