Make the grits: In a medium saucepan, bring the water and salt to a boil. Whisk in the grits, then return to a boil. Reduce the heat to low, cover, and cook until the grits are tender, 20 to 30 minutes. If your grits are too thick or sticking to the pan, add a little water to make them creamy. Remove from the heat and stir in the butter. Cover to keep warm.

Make the sauce: In a medium saucepan, heat the olive oil over medium heat. When the oil is shimmering, add the shallot and garlic and sauté until softened, 2 to 3 minutes. Add the thyme and wine and bring to a simmer. Cook until the wine is reduced by half, 2 to 3 minutes. Add the cream, seasoning, and salt. Bring to a boil, then reduce the heat to medium low and simmer until the cream is reduced by one-third, 2 to 3 minutes. Add the spinach and cook until wilted, 2 minutes. Remove the pot from the heat and cover to keep warm. (Discard the thyme sprig.)

Make the grouper: In a small bowl, mix the salt, pepper, and seasoning. Lightly coat the fish with oil, then rub all over with the seasoning mixture.

In a large skillet, heat the 2 tablespoons olive oil over medium-high heat. When the oil is shimmering, add the fish. Gently press the fillets down with a spatula so they don't buckle. Cook until golden brown, about 4 minutes. Flip and cook on the other side until golden brown and cooked through, about 4 minutes.

Serve the fish and grits with the spinach and sauce on top and lemon slices alongside.