Preheat the oven to 350°F. Pat the salmon dry and place, skin side down, on a roasting rack.

In a large saucepan on medium, add 1 tablespoon of butter and the garlic and onion. Cook until translucent, stirring constantly. Remove from the pan and set aside.

In the same pan, add the remaining 2 tablespoons of butter and reduce heat to low. Cook for 5-8 minutes, stirring constantly, until the butter is foaming and turning brown. Add the garlic/onion mixture back to the pan, along with the walnuts and cranberries. Cook on low for another 2-3 minutes. Remove from heat and spoon the mixture over the salmon. Season to taste with salt and pepper.

Place the salmon in the oven, uncovered, and cook for 25-30 minutes or until cooked through. For extra holiday flair, grate some fresh nutmeg on top before serving.