Preheat oven to 400 degrees. Line a rimmed baking sheet with aluminum foil.
BROCCOLI: Pile broccoli in a mound in center of baking sheet. Drizzle 2 1/2 tablespoons olive oil over broccoli along with garlic and toss to evenly coat. Season with salt and pepper to taste and spread near edges of baking sheet, leaving enough space in center to fit salmon fillet.
SALMON: Place salmon in the center of baking sheet, leaving about 3/4-inch between fillets so they can evenly cook.
In a mixing bowl whisk together mayonnaise, lemon juice and garlic and brush about 1/2 Tbsp over each fillet. Season top with salt and pepper.
In a mixing bowl whisk together parmesan, bread crumbs, parsley, lemon zest and thyme, then drizzle 1 1/2 Tbsp olive oil into bowl and stir with a fork until evenly moistened.
Spread parmesan mixture evenly over tops of salmon fillets.
Bake until salmon fillets have cooked through, about 12 - 15 minutes depending on the thickness of the fish. (for a more golden crust you can broil during the last 1 - 2 minutes of baking if needed).