01 - Preheat oven to 400°F. Line a large baking sheet with parchment paper.
02 - In a small bowl, mix butter, garlic, parsley, and lemon zest until smooth.
03 - Arrange asparagus, snap peas, and peas evenly on one side of the baking sheet. Drizzle with olive oil, season with salt and pepper, and toss to coat.
04 - Place salmon fillets on the other side of the baking sheet. Pat dry, season with salt and pepper, and top each fillet with garlic butter and a couple of lemon slices.
05 - Roast in the oven for 12–15 minutes, until the salmon is just cooked through and the vegetables are tender.
06 - Remove from oven and immediately toss the hot vegetables with baby spinach so it wilts slightly from the residual heat.
07 - Serve each salmon fillet atop a bed of roasted greens, spooning any remaining pan juices over the top.