025 / 75 · Noodles, Grains and Pantry Bakes

Mushroom Buckwheat Sour Cream Bake

One 9-in/23-cm square dish, at least 3 qt/2.8 L; 4 main-dish portions · Active 35 min · Total 1 hr 45 min

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Roasted buckwheat groats have a character of their own beside browned mushrooms and a lightly set sour-cream filling. This is a grain-forward supper, finished with chopped walnuts rather than a blanket of cheese. The groats are cooked gently and left to stand before mixing, so they stay separate instead of becoming a thick porridge.

Jump to ingredients

Drawn mushroom and buckwheat sour-cream bake with chopped walnuts.

Roasted groats still need cooking

Buy plain roasted buckwheat groats, sometimes labeled kasha, rather than buckwheat flour or a seasoned instant packet. Rinse if the package directs, then use its water ratio when it differs from the amount given. Keep the simmer gentle and avoid repeated stirring once the pan is covered. A short off-heat rest helps the remaining water distribute through the grains. They should be tender with a little shape left, not hard at the center. Roasting on the package describes flavor and processing, not permission to skip the boiling stage. Let the cooked groats release steam briefly before they meet the egg-and-dairy mixture.

Brown the mushrooms before tempering the filling

Cook the mushrooms in two batches, because five hundred grams crowded into one layer would mostly steam. Soften the onion separately and then reunite everything. Take the skillet off the heat and cool the vegetables until warm. Whisk sour cream, eggs and stock smoothly in a bowl before folding in the grain and mushrooms; a very hot skillet would start setting the eggs in streaks. The oven makes the final light binding, and several center checks confirm it has reached the casserole endpoint. Add the ready-to-eat walnuts near the end so they toast lightly without burning. Their presence needs a clear label at a shared table. The recipe title does not tell a guest that nuts are part of the base meal.

Ingredients

  • About 1 1/2 cups plain roasted buckwheat groats (250 g), weighed
  • 3 cups water (720 ml), or the groat-packet amount for 250 g
  • 2 tablespoons neutral oil (30 ml), divided equally between mushroom batches
  • 1 lb 2 oz mushrooms, thickly sliced (500 g)
  • 1 tablespoon butter (15 g)
  • 1 medium onion, finely chopped (150 g)
  • 1 teaspoon dried thyme
  • 1 cup sour cream (240 g)
  • 2 large eggs
  • 1/2 cup low-sodium vegetable stock (120 ml)
  • 1/4 teaspoon fine salt (1.5 g)
  • 1/4 teaspoon black pepper
  • 1/3 cup walnuts, roughly chopped (40 g)

Set out

Oven, 9-in/23-cm square baking dish, at least 3 qt/2.8 L, Covered saucepan, 12-in/30-cm skillet, Two bowls, Whisk, Rimmed baking sheet, Food thermometer, Suitable foil for loose shielding if the topping colors before the center finishes

Allergens

Milk, Egg, Tree nuts: walnuts, Buckwheat; check groat labels for wheat cross-contact if relevant. Check labels and substitutions.

Make it

  1. Cook groats in their water or packet amount: bring to a simmer, cover and cook gently 12–15 minutes, or packet time, without frequent stirring until water is absorbed and grains are tender. Stand covered off the heat for 10 minutes, then uncover and release steam.
  2. Meanwhile heat oven to 375°F (190°C) and set the dish on a rimmed sheet. Heat 15 ml oil in the skillet over medium-high heat. Brown half the mushrooms 7–9 minutes until their released water evaporates. Transfer to a bowl and repeat with remaining oil and mushrooms.
  3. Melt butter in the skillet over medium-low heat and cook onion 7–9 minutes until soft. Return mushrooms and add thyme. Take off the heat and cool 10 minutes until warm rather than hot.
  4. Whisk sour cream, eggs, stock, salt and pepper in the second bowl. Fold in warm groats and mushroom mixture, then spread in the dish. Bake 25 minutes. Scatter walnuts and bake 10–15 minutes more until filling is set and the center and several other spots reach 165°F (74°C). Shield walnuts loosely if needed while the center finishes.
  5. Rest 5 minutes before serving four portions.

Let the groats keep their identity

Fold with a broad spoon rather than whisking once the grains are added. Visible individual groats and thick mushroom slices distinguish this dish from a smooth cream casserole.

A useful detail

The 105-minute total includes cooking and resting the groats, two mushroom batches, cooling before the egg mixture and up to 40 minutes baking. Use the groats’ actual packet instructions and allow any longer cooking time.

Another way

  • For a version without walnuts, omit them and scatter 40 g coarse fresh breadcrumbs tossed with 2 teaspoons/10 ml olive oil during the same late topping stage. This adds wheat; use bread suitable for the eaters and update the allergen label.

Keep it well

Refrigerate shallow portions within 2 hours, or 1 hour above 90°F (32°C), at 40°F (4°C) or below. Use within 2 days or an earlier dairy or cooked-grain deadline. Reheat to 165°F (74°C). Refrigeration is preferable to freezing the sour-cream-and-egg filling, which can separate and become grainy.