In a small bowl, whisk together the maple syrup, apple cider, Dijon mustard, soy sauce, and a pinch of salt and pepper. Set aside.
Heat olive oil in a large skillet over medium heat. Season the salmon fillets with salt and pepper. Place the salmon skin-side down in the skillet and cook for about 4 minutes.
Carefully flip the salmon fillets and pour the maple cider glaze over the top. Cook for an additional 4-5 minutes, basting occasionally, until the salmon is cooked through and flakes easily with a fork. Remove from heat.
While the salmon is cooking, bring 4 cups of water to a boil in a medium saucepan. Gradually whisk in the polenta, stirring constantly to avoid lumps. Reduce heat to low and cook for about 5-7 minutes, stirring frequently, until thickened.
Stir in the butter, honey, and Parmesan cheese (if using) into the polenta until well combined. Season with salt to taste.
To serve, spoon the honey butter polenta onto plates, top with the glazed salmon, and drizzle any remaining glaze over the top. Garnish with chopped parsley if desired.