Preheat oven to 375°F and line a large, rimmed baking sheet with a piece of parchment paper or silicone baking mat.
Place salmon fillets on the prepared baking sheet and generously season with salt and black pepper, to taste. Set aside.
In a small bowl, whisk together olive oil and lemon juice. Add the mustard, honey, and garlic and whisk to combine. Brush each fillet with the honey-mustard mixture until coated.
In a small bowl, combine chopped pistachios and cardamom. Evenly divide the mixture between the salmon fillets and press gently into the fish.
Roast at 375°F until the salmon is flake, about 13-15 minutes. Serve immediately.