Pat salmon fillets thoroughly dry with paper towels. Season both sides evenly with garlic powder, salt, and black pepper.

Heat 1 tablespoon olive oil and 1 tablespoon butter in a large heavy skillet or cast-iron pan over medium-high heat until shimmering.

Add salmon fillets flesh-side down. Sear undisturbed for 4 to 5 minutes until a deep golden, crisp crust forms. Flip carefully and cook for an additional 3 to 4 minutes until almost cooked through. Transfer to a warm plate.

Reduce skillet heat to medium. Add remaining olive oil if pan is dry, then add minced garlic and sun-dried tomatoes. Sauté for 1 minute until highly aromatic.

Pour in the broth to deglaze the skillet, scraping up all flavorful browned bits from the bottom.

Pour in heavy cream and bring to a gentle simmer. Cook for 3 minutes until slightly reduced.

Stir in grated Parmesan cheese until melted and silky smooth. Add baby spinach and cook for 1 to 2 minutes until wilted into the sauce. Stir in fresh lemon juice.

Nestle the seared salmon fillets back into the skillet with any accumulated resting juices.

Spoon the velvety Tuscan garlic sauce generously over top. Simmer gently for 1 minute until heated through.

Garnish with fresh basil chiffonade and lemon wedges. Serve immediately over warm pasta, rice, or with crusty bread.