Chewy Korean Rice Cakes and Mushrooms Are a Creamy Umami Flavor Bomb

Name: Chewy Korean Rice Cakes and Mushrooms Are a Creamy Umami Flavor Bomb
Ingredients: 5 cups heavy cream; 1 cup crème fraîche; 3/4 cup doenjang (Korean fermented bean paste, such as Chung Jung One); 2/3 cup finely chopped yellow onion (about 1 small onion); 1/3 cup minced garlic (about 1 large garlic head); 2 tablespoons mushroom powder (such as CJ Foods) or bouillon; 2 tablespoons soy sauce; 1 teaspoon garlic powder; 1 teaspoon onion powder; 2 pounds mixed mushrooms (such as shiitake, shimeji, oyster, or hen-of-the-woods), trimmed; 2 pounds cylinder-shaped Korean rice cakes (such as Apexy); Finely chopped fresh chives , for garnish