In a large saute pan over medium heat, add the canola oil and heat the oil to a slight smoke. Add 1 sprig of fresh thyme to the saute pan and sear the sea bass skin side down for 3/4 of the cooking time about 7 minutes. This will give the fish a beautiful crisp skin and golden color.
While the fish is cooking start the grits. In a 2 quart saucepot add 2 tablespoons of butter and 1 sprig of fresh thyme. When the butter begins to brown, add the mushrooms and saute until golden. Using a wooden spoon, stir in the grits, add the chicken stock, and reduce to a simmer. When the grits begin to thicken finish with heavy cream and 1 tablespoon of butter. Season with salt and pepper, when ready to serve, remove the thyme sprig. Keep the grits warm on a low temperature.
Carefully turn the fish over, to finish the other side. Remove the sea bass and hold in a warm place.
In the same saute pan, on the same temperature, add the spinach. It will quickly wilt. Finish the spinach with the remaining whole butter and season with salt and pepper.
For presentation, serve this dish in a large soup bowl. Using a ladle, scoop a small amount of grits into the bottom of each bowl. Layer a small amount of spinach on the grits and finish with the sea bass. Garnish with fresh thyme.