In a large skillet, heat the olive oil over medium heat. Season the salmon fillets with salt and pepper on both sides.
Place the salmon fillets skin-side down in the skillet and cook for about 4-5 minutes, until the skin is crispy.
Carefully flip the salmon fillets and add the butter and minced garlic to the skillet. Cook for an additional 3-4 minutes, basting the salmon with the melted garlic butter.
Once the salmon is cooked through (internal temperature should reach 145°F), remove it from the skillet and set aside.
In the same skillet, add the fresh spinach and lemon juice. Sauté for 2-3 minutes until the spinach is wilted.
Serve the salmon on a bed of sautéed spinach, drizzling any remaining garlic butter from the skillet over the top. Garnish with fresh parsley.