Combine the butter, chopped jalapeño and lime zest. (Reserve the rest of the lime for squeezing over the finished fillets)
Lightly spray a heavy baking dish (like a cast iron skillet) and place the fillets skin side down. Season well with salt and pepper. Place two small pats of the jalapeño lime butter on each fillet. Roast for 25-30 minutes until the salmon flakes easily.