This lentil and mushroom gravy over mashed rutabaga-potatoes with brown butter and crispy sage is a hearty, nutrient-dense comfort meal. This award-winning recipe—recognized as “Best Written Recipe” by Bauman College—builds rich, savory flavor from lentils and mushrooms paired with a creamy rutabaga-potato puree. Finished with nutty brown butter and crispy sage, it delivers flavors reminiscent of a holiday meal while showcasing the power of simple, whole-food cooking.
I originally created this recipe for Bauman College, where it was recognized as “Best Written Recipe” for their Mighty Lentil recipe writing contest and is now featured on their blog.
The challenge I accepted was to create a vegetarian winter dish that put lentils in the spotlight while writing for the Bauman audience. I focused on techniques I learned as a student—including soaking legumes and building rich, flavorful sauces—to create a dish that is both approachable and satisfying. The inspiration was my mom’s hamburger gravy, a simple, hearty meal that brought everyone at the table together. In this vegetarian version, lentils and mushrooms create a deeply savory, umami-rich flavor without the need for meat. The rutabaga-potato purée is a nod to my mother, who adores rutabaga, and to our family’s love of my grandmother’s pasties.
Why This Recipe Works
This recipe works because it layers flavor and texture from simple, whole ingredients. Lentils and mushrooms create a deeply savory, umami-rich gravy without the need for meat, while rutabaga and potatoes blend into a creamy, balanced puree. Brown butter adds richness, and crispy sage brings a fragrant, slightly crunchy finish that ties the entire dish together.
What Makes This Meal Nourishing
Lentils provide plant-based protein and fiber, while mushrooms contribute B vitamins—all brought together in a rich, savory sauce. This nutrient-dense gravy is served over rutabaga, an often-overlooked cruciferous vegetable, whipped with potatoes, browned butter, earthy sage, and oat milk for a creamy, balanced base. Rutabaga provides glucosinolates—beneficial compounds linked to long-term health—while potatoes add potassium and satisfying carbohydrates. Serve with a green salad dressed in a light vinaigrette to complement the richness and round out the meal.
How to Make This Recipe
1. Prepare the Lentils. Soak the lentils overnight to save time and improve digestibility. Pre-soaking reduces phytic acid, making the nutrients in lentils more bio-available and easier on the stomach. Then cook them according to package instructions—soaking means they’ll cook faster than usual. Doing this step ahead of time not only boosts the nutrition but also makes assembling this meal later quick and stress-free.
2. Cook the Rutabaga-Potatoes. Boil until tender, then mash or whip with brown butter (below) until smooth.
3. Make Brown Butter and Crispy Sage. Gently brown butter until nutty, then crisp the sage leaves.
4. Prepare the Lentil Mushroom Gravy. Sauté mushrooms with aromatics, create roux, then simmer into a thick, savory gravy.
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Lentil and Mushroom Gravy over Mashed Rutabaga-Potatoes with Brown Butter and Crispy Sage
Ingredients
For the Whipped Rutabaga-Potatoes with Brown Butter and Crispy Sage
- 1 pound rutabaga peeled and cut into 1-inch pieces
- 1 pound potatoes Yukon Gold, peeled and cut into- 1-inch pieces
- 4 tablespoons butter 1/2 stick
- 12 – 16 leaves sage 4 – 6 large leaves left whole for garnish; remaining leaves thinly sliced/chiffonade, about 1 tablespoon
- 2 cups oat milk or milk of choice
- salt and pepper to taste
For the Lentil and Mushroom Gravy
- 2 tablespoons olive oil
- 1 cup onion small dice (about 1 small or 1/2 medium)
- 8 ounces mushrooms cremini, ends trimmed and cut into 1/4-inch dice
- salt and pepper
- 1/2 teaspoon thyme dried
- 2 cloves garlic minced
- 2 tablespoons butter
- 4 tablespoons spelt flour or thickening flour of choice
- 2 cups vegetable broth
- 1 1/3 cups lentils green, preferably soaked overnight—see recipe note
Instructions
For the Whipped Rutabaga-Potatoes with Brown Butter and Crispy Sage
- Place rutabaga in a pot and cover with salted water by 3 inches. Bring to a boil and reduce to a simmer for 15 minutes to give the rutabaga a head start. Add potatoes and continue to simmer until both vegetables are fork-tender, about 10 minutes more. When rutabaga and potatoes are tender, drain, set aside, and keep warm.
- While rutabaga and potatoes are cooking, heat butter in small saucepan over medium heat. Once butter is melted and gently bubbling, add 4 to 6 whole sage leaves and toss to coat in hot butter. Monitor the heat to prevent sage leaves from burning. Let sage get crispy, but not brown. Transfer sage leaves to a plate with a paper towel, sprinkle with salt, and set aside. Next, add the chiffonade sage to the butter and let crisp as the butter continues to brown. (Optional: after butter and sage are toasted reserve 1 tablespoon of brown butter and sage for plating). Add 2 cups of oat milk to the toasted butter mixture and gently heat as the rutabaga-potato finishes cooking.
- To finish the rutabaga-potatoes, use masher to break down drained vegetables. Add warm milk and reserved brown butter-milk mixture and continue to mash. Leave chunky for a rustic look or use hand mixer or stick blender to whip mixture into a smoother puree. Season to taste. Keep covered and warm on low burner or warm oven while making lentil gravy.
For the Lentil and Mushroom Gravy
- Heat a 10-inch sauté pan over medium heat and add olive oil. Sauté onion until softened, about 5 minutes. Add in mushrooms, sprinkle with salt and pepper. Continue to cook down until glistening (about 12 minutes), stirring occasionally. Add thyme and garlic and sauté for another 2 minutes.
- Add 2 tablespoons butter to mushroom and onion mixture and mix well. Add 4 tablespoons of flour and mix into a roux with the mushrooms and onions. Continue to stir and toast the flour for a few minutes.
- Slowly add the vegetable broth while scraping the bottom of the pan to incorporate the flour into the broth.
- Add cooked lentils to the broth and continue to stir until gravy is thickened. Season to taste.
- To serve add a scoop of the mushroom-lentil gravy to a bed of rutabaga-potato puree. Garnish with crispy sage leaf and the optional brown butter drizzle.
Notes
Soaking lentils in advance may improve digestibility and nutrient absorption, while also reducing cooking time and making the final dish quicker to prepare.
To prepare the lentils for this recipe, bring 3 1/2 cups of water to a boil in a medium pot. Add the pre-soaked lentils and maintain a gentle simmer until tender, about 20 minutes. Drain any excess water as needed. Allergen Information Wheat, Gluten, Dairy, Nightshades
