Make the Meatballs: Preheat oven to 475 degrees. Combine all ingredients in the work bowl of a stand mixer. Mix on medium low until just combined. Increase speed to medium and whip until mixture is light and fluffy, about 5 minutes, scraping the sides of the bowl from time to time. If you don't have a mixer, simply mix the ingredients in a large bowl with your hands until they come together.
Using a tablespoon measure, transfer tablespoonfuls of the mixture to a sheet pan. With damp hands, roll into balls. Chill (up to 24 hours) until ready to bake.
Transfer sheet pan to oven and bake until meatballs are browned and cooked through, about 12 minutes. Remove from oven and transfer meatballs to a plate. Pour ⅓ cup hot water onto the baking sheet and scrape up the brown bits that are stuck to the bottom using a metal spatula. Poor liquid and any bits into a measuring cup and set aside.
Make the Gravy: Melt butter in a 12 inch nonstick skillet over medium heat. Add flour and cook for one minute, whisking constantly. Slowly add reserved drippings from meatballs, chicken broth, beef broth and soy sauce, whisking constantly. Bring to a simmer and continue cooking until reduced slightly, about 5 minutes. Add cream and return to a simmer. Season to taste with salt and pepper.
Add meatballs to gravy and cook briefly to reheat. Garnish with chopped parsley or chives if desired. Serve with lingonberry jam or No Cook Lingonberry Sauce and Quick Swedish Pickled Cucumbers..