There’s something about a warm, rich Mushroom Gravy that makes mealtime feel extra cozy! This recipe uses sautéed onions, carrots, and celery to build a flavor-packed base, then it is blended with beef broth and herbs to create a silky smooth gravy. There is no flour or added thickeners in this recipe! Kelley’s Tips Before You Get Started Take time to caramelize the veggies.