Melt 3 Tblsp (a quarter of total) butter in sautee pan over medium heat. Add onions and sautee until beginning to soften. Add peas, then stock/water. Bring to simmer, then simmer peas for about 90 seconds.Add peas, onions, and liquid to blender with cottage cheese. Blend until light and creamy, adding more liquid if needed. Finally, add mint and process again. Taste for seasoning.
Melt 3 Tblsp butter (a quarter of total) in same sautee pan. Add carrots, seasoning with salt and pepper to taste. Cook until al dente and slightly golden. Remove from pan and set aside.
Turn broiler on high to preheat. Melt 6 Tblsp butter (half of total) in same sautee pan. Place salmon skin side down in pan. Season with salt and pepper. When butter is bubbling, baste salmon with it. Repeat every couple of minutes until bottom half of salmon fillet looks cooked from the side. Place sautee pan under the broiler and complete cooking the fish, 4-6 minutes depending on thickness.
To plate, evenly divide pea puree between pasta bowls. Top with a piece of salmon, then evenly divide carrots between plates. Sprinkle with chopped pistachios and garnish with a mint sprig. Voila! Dinner is served!