Serve this hearty gravy with rice, pasta or potatoes.
Cook onion and garlic in 2 teaspoons broth in a pan over medium-high heat until soft, stirring occasionally. Lower heat to medium. Add mushrooms and soy sauce and continue cooking, stirring to prevent sticking.
In a bowl, stir together the remaining 2 cups broth, liquid smoke and arrowroot powder. Whisk well. Turn heat back up to medium high. Slowly pour broth mixture into the pan, whisking vigorously to prevent lumps. Allow gravy to come to a boil and boil for at least 1 minute. Remove from heat and add thyme, salt and black pepper. Stir to mix well. Serve.