Creamy Cabbage Soup with Chive Oil and Cumin Seeds

Name: Creamy Cabbage Soup with Chive Oil and Cumin Seeds
Ingredients: 6 tablespoon unsalted butter; 2 cup chopped yellow onion; 1 ½ teaspoon kosher salt (divided); 1 clove garlic (peeled and crushed into a pulp); 4 cup Savoy cabbage (cut into thin ribbons); 1 ½ cup water (plus more if needed); 1 cup whole milk (plus more if needed); ½ cup cream; ¼ cup crème fraîche; ¼ teaspoon finely grated lemon zest; 1 dash red Tabasco sauce; chive oil (as needed, see recipe); freshly toasted cumin seeds (to taste)