For the sausage gravy: Heat a pan over high heat, add the oil and then add the sausage. Brown the sausage, stirring and breaking up the large chunks, until cooked through. Add the chile powder, thyme and cayenne and saute for 1 minute. Stir in the flour to make a roux. Slowly stir in the milk and bring the gravy to a simmer. Reduce the heat to a simmer and cook for 10 minutes, stirring so the sauce does not burn. Season with salt and pepper. Keep warm.
For the vegetables: Preheat the oven to 400 degrees F.
Toss the potatoes in a bowl with 2 tablespoons of the grapeseed oil, 1 teaspoon kosher salt and 1/2 teaspoon black pepper. Spread the potatoes on a baking sheet and bake until tender and browned, 20 to 25 minutes.
Heat a large saute pan over high heat. Add the remaining 2 tablespoons oil to the pan. Add the potatoes, tomatoes and garlic to the pan and saute for 2 to 3 minutes. Add the kale to the pan and saute to wilt the kale. Add a little water to help with the wilting if needed. Season with salt and pepper and a squeeze of lemon juice.
For the trout: Season the trout with the salt and pepper.
Heat a large skillet over high heat. Add the oil to the skillet and then gently place the fish flesh-side down in the skillet. Sear the fish on the flesh side for 2 to 3 minutes and then flip and cook until the skin is crispy and the flesh is fully cooked, another 2 to 3 minutes. Allow the fish to rest briefly before serving.
For plating: Divide the vegetables among 6 plates, lay the fish (flesh-side up) over the vegetables and then spoon the sausage gravy over the top of the fish.