Go Back
Overhead picture of Porcini Mushroom, Greens, and Forbidden Rice Gratin ready to eat.

Porcini Mushroom, Greens and Forbidden Rice Gratin

This gratin makes a hearty main dish or a delicious side. It won't last long! This recipe is vegetarian and easily gluten free.
Look for porcini mushrooms on the natural food isle, dried. They'll need to be reconstituted.
Course Dinner, Main Course
Cuisine American
Keyword Black Rice Casserole
Servings 5 -6 as Main Dish
Calories 612kcal
Author Vanilla And Bean


  • 1 oz Dried Porcini Mushrooms 28g
  • 1 C Forbidden Black Rice 194g
  • 4 1/2 C Yellow or Sweet Onions sliced into thin 1/2 moons (about 2 large onions) 344g
  • 1 Tbs Coconut Oil Virgin, Unrefined* (see note)
  • 2 Tbs Butter divided
  • 1 tsp Sea Salt divided
  • 1 tsp Pepper divided
  • 2 1/2 C Kale, chopped 104g
  • 2 C Rainbow or Swiss Chard, chopped 118g
  • 1 1/2 C Bread Crumbs** Gluten Free if needed 116g, see note
  • 8 oz Gruyere grated, 227g
  • 1/2 tsp Fresh Thyme chopped
  • 1/4 tsp Nutmeg
  • Fresh Thyme for Garnish


  • Bring 2 C of water to boil. Place porcini in heat proof bowl and pour the boiling water over the porcini. Cover for 30 minutes to soften the porcini.
  • Put the black rice on to cook. Fill stock pot with rice, a pinch of sea salt and 2 C water. Bring to a boil, turn the stove to low, cover and cook for about 30 minutes. When cooking is complete, the rice will be tender and no water will remain. Place rice in large mixing bowl. Set aside.
  • Cut the onions in half and slice length wise so that your slices are thin and long. Melt the coconut oil and 1 Tbs butter in a large non stick sauté pan. Place the onions in the pan with 1/2 tsp salt and 1/2 tsp pepper. Cooking on medium to low heat, these will take about 30 minutes to caramelize. Don't rush them else they'll burn. Low and slow here. Stir occasionally.
  • For the greens, wash the kale and chard. De-stem the kale. Ribbon the greens by rolling the leaves up, length wise, then cutting about 1/2" ribbons. Then, rough chop the ribbons in 1/2. Set aside.
  • Melt 1 Tbs butter and mix it into the bread crumbs. Set aside.
  • Preheat the oven to 375F (190C). After the porcini have softened, strain the porcini through cheese cloth, reserving the broth. Squeeze the cheese cloth so that the broth is extracted from the porcini. Give the mushrooms a good rinse in a sieve to make sure they are free from debris. Rough chop the porcini and place them in the large mixing bowl with the rice. Strain the broth through the sieve again. Measure out 1/3 C (80g) of the broth and set aside. Freeze or refrigerate the remaining broth for future use.
  • When the onions are done caramelizing, add the greens to the sauté' pan, with the onions. This may be done in batches if needed. When the greens just start to wilt, pull them from the pan and put them in the large mixing bowl with the cooked rice and porcini.
  • In the large mixing bowl, mix all the rice, porcini, greens, caramelized onions, 1/2 the grated gruyere, thyme, nutmeg, and 1/2 tsp salt and 1/2 tsp pepper. Mix to evenly distribute the ingredients. Taste to check seasoning. Now is a good time to adjust if necessary.
  • Prepare a 3-4 Quart casserole by spraying it with cooking spray. Pour the rice/greens mixture in the dish, smoothing it out. Pour a 1/3 C (80g) of the broth over the mixture. Spread the remaining gruyere over the top, then top the gratin with the breadcrumbs. Bake uncovered for 25 minutes. Garnish with fresh, chopped thyme.
  • Store in a covered container for up to three days.


*I use unrefined coconut oil for most of my cooking and baking. You will not taste coconut in the recipe. I reserve olive oil mostly for roasting, salad dressing, drizzling and dipping, but it can be subbed here if needed.
**For homemade breadcrumbs, process five pieces of bread in a food processor, then bake the crumbs at 325F (163C) for about 30 minutes, stirring once, to dry them out. Use gluten-free if necessary.
Adapted from The Smitten Kitchen Cookbook.


Calories: 612kcal | Carbohydrates: 74g | Protein: 25g | Fat: 25g | Saturated Fat: 15g | Cholesterol: 62mg | Sodium: 948mg | Potassium: 699mg | Fiber: 6g | Sugar: 9g | Vitamin A: 4799IU | Vitamin C: 55mg | Calcium: 617mg | Iron: 3mg