Pat the skin of the branzino dry with a paper towel, then using a sharp knife, score the skin approximately 1/2" apart. Season with S&P.
Heat a sauté pan over high heat. Add canola oil. Allow to just reach the smoking point, then add the branzino skin side down. Do no touch the fish for about 30 seconds, allowing it to relax in the pan. Lower the heat to medium, then using a fish spatula, gently lift the fish on the side to ensure that oil runs underneath all sections of the skin, then gently press the fish down to ensure all of the skin is in contact with the hot oil and pan.
Once the skin is golden brown and crisp and the fish is still slightly under cooked in the center, spread the Tuscan Butter over the fish, then remove from the pan and transfer skin side up to a sizzle platter.
Drain any excess oil from the pan. Add shallots, and capers, allowing to lightly caramelize.
In a large sauté pan, melt Tuscan butter, then add spinach and S&P Mix. Cook over medium heat, timing the cooking to allow the spinach to remain bright green and just barely wilt prior to plating the dish. Taste and adjust seasoning as needed.
Add lemon juice, S&P, and parsley to the butter sauce. Taste and adjust seasoning as needed.
Drain spinach of any excess liquid by resting on a paper towel lined sizzle platter. Spoon spinach onto the left side of the plate as shown in the photo.
Spoon the sauce over and around the spinach as shown in the photo.
Warm the fish, only if needed in the oven for 1 minute, then transfer to the plate as shown in the photo.