Chef John's Butternut Bisque

Ingredients (11)

• + 3 tablespoons butter add to pantry
• + 1 large onion, diced add to pantry
• + 1 teaspoon kosher salt, plus more to taste, divided add to pantry
• + 1 (2 pound) butternut squash add to pantry
• ✓ 2 tablespoons tomato paste
• + 1 quart chicken broth add to pantry
• + 1 pinch cayenne pepper add to pantry
• + ½ cup heavy cream or creme fraiche, plus more to garnish add to pantry
• + 2 tablespoons maple syrup, or to taste add to pantry
• + Chopped fresh chives for garnish add to pantry
• + Pomegranate seeds for garnish add to pantry