Kale, Barley Mushroom Gratin

My first memory of barley was in my Grandmother’s beef barley soup. It was thick and hearty with a savory broth and tons of chewy pearl barley.

I loved it so much I came up with a vegan mushroom barley soup for variation and my favorite ham and vegetable soup with barley and fresh herb pistou.

If you think barley is relegated strictly to soups, it’s not. Try it in this hearty vegan kale and barley chopped salad or today’s recipe, a rich mushroom kale and barley au gratin casserole. It’s rich, meaty (though there’s no meat in it) and satisfying. This kale and mushroom casserole makes a delicious side dish or vegetarian main course.

What is pearl barley?

Barley is an ancient cereal grain with a mild flavor and toothsome texture. It comes hulled, hull-less, pearled, flaked or even in barley grits.

Hulled and hull-less barley are the most nutritious types of barley with the hulled variety only having the inedible outer hull removed.

Hull-less barley has the bran and germ intact and is still considered a whole grain.

Pearl barley is more processed with the bran layers removed and thus, slightly less nutritious, however, it takes less time to cook and still has more nutritive benefits than other more highly processed grains.

What’s the best way to cook pearl barley?

Barley expands nearly 3 times when cooked, so one cup of dry pearl barley will yield about 3 cups of cooked barley.

1. To cook pearl barley, bring a large pot of water to a boil add a few pinches of salt and stir in the grains.
2. Reduce the heat to a rapid simmer, stirring occasionally and cook until tender. It usually takes about 25 to 30 minutes. Note, you can use hulled or hull-less barley in this recipe, but it will need a longer cooking time to absorb the water and plump.
3. Once the barley is tender, transfer it to a mesh strainer and drain off the excess liquid.

If you’re a barley fan, I recommend making a double batch and storing the excess in the refrigerator for up to 5 days to use in soups, stews or salads. (You’re more likely to reach for this wholesome ancient grain if it’s already cooked.

When cooked, pearl barley has a kind of soft, velvety texture that gives this ancient grain a unique mouth feel.

Ingredients for kale mushroom casserole with barley

There’s also a simple parmesan breadcrumb topping that adds a golden crunchy crust, but you can also use panko if it’s more convenient.

I recommend cooking the vegetables in two stages with the mushrooms garlic and thyme first and the onions and kale second as they will cook at different rates and in order to coax the best texture and flavor from the mushrooms and kale cook them in batches. Here’s how:

How to cook the vegetables for the gratin

1. Heat the olive oil in a skillet (preferably nonstick) and add the mushrooms and a pinch of kosher salt.
2. Cook for 5-7 minutes, stirring occasionally until the mushrooms are golden and have given up some of their liquid.
3. Stir in the chopped garlic and thyme and cook for one minute more, until fragrant. Transfer the mushrooms to a bowl.
4. Heat the remaining olive oil in the same skillet and sauté the onions until tender and slightly translucent.
5. Add the kale and place the lid securely on the skillet.
6. Remove the pan from the heat and allow the kale to wilt from the residual heat from the pan and the onions.
7. Transfer the kale and onion mixture to the bowl with the mushrooms and set aside.

Cheese sauce for the barley and mushroom casserole

You can use the same skillet to make the cheese sauce for the casserole, no need to rinse or clean it. You’re welcome…

This sauce is similar to a traditional velouté, but made lighter because it doesn’t contain cream or egg yolks the way the classic recipe calls for. Broth blended with the roux makes the sauce lighter, but with the same creamy mouth feel.

To keep it vegetarian, use a vegetable broth like this one made from kitchen scraps or a low-sodium store-bought variety (you can also use chicken broth).

How to make cheese sauce for the kale mushroom casserole

1. Melt the butter in the skillet and when it’s bubbly and foamy, sprinkle in the flour, salt and pepper and grated nutmeg, stirring constantly.
2. Cook the flour mixture until there are no dry bits of flour left and the paste is bubbly, about one minute.
3. Gradually add in the broth, stirring constantly to blend the liquid with the roux (butter and flour mixture) until its creamy and emulsified.
4. Remove the pan from the heat and add the Gruyere cheese, stirring until the cheese has melted.
5. Stir in the vermouth and taste the sauce for seasonings. Adjust as necessary.

Assembling the casserole

Now that all the components are cooked, it’s time to assemble the whole grain kale and mushroom casserole. Add the cooked barley, and vegetables to the cheese sauce and stir until the mixture is well combined, then transfer to a 1 quart baking dish.

Serving the vegetarian casserole like a risotto

To be honest, you don’t have to bake this mushroom and barley gratin as a casserole, especially if you’re pressed for time.

Instead, serve the mushroom and barley gratin straight from the skillet as a sort of barley risotto. Its absolutely delicious as it puddles on your plate.

However, if the idea of a bubbly center and crunchy golden crust appeals to you, then go for it. You can make it in about 2 minutes with a mini food processor.

Crispy breadcrumb topping for the barley mushroom casserole

Just add pieces of torn sourdough bread, a little butter, grated parmesan cheese and fresh parsley to a mini prep processor and pulse until fine crumbs form. Sprinkle the cheesy breadcrumb topping evenly over the casserole and bake until the kale barley and mushroom gratin is bubbly and hot and the breadcrumbs are browned and crisp.

What does the vegetarian casserole taste like?

This is like a sophisticated mac and cheese without the mac. In fact, my tasters liked it BETTER. The barley is tender with a nice chew and the mushrooms give the casserole a meaty texture and flavor. The kale isn’t a predominant flavor, but the beautiful ribbons of toothsome greens add a visual appeal.

I have to say, though, it’s the cheese sauce that MAKES this tempting side dish. It’s rich and luxurious. The hint of vermouth plays well with the Gruyere elevating this simple barley side dish to a completely different level.

My tasters kept going back for spoonful after spoonful because it’s just THAT GOOD.

What to serve with mushroom and barley casserole

You can enjoy this gratin with anything you’d normally serve potatoes with. It’s very versatile and compliments most meats and seafood. It’s also hearty enough to enjoy as a vegetarian main course with a simple green salad.

Try this as a side dish with:

• Grilled Herb Crusted Veal Chops
• Pesto Salmon
• Herb Roasted Chicken with Pan Gravy
• Cast Iron Ribeyes with Bearnaise Butter
• Pan Roasted Chicken Breasts
• Herb Crusted Rack of Lamb
• Cilantro Lime Fish Kebabs
• Bourbon Marinated Flank Steak
• Young Chicken in a Cast Iron Skillet
• Apple Cider Brined Smoked Pork Loin
• Marinated Roast Turkey Breast
• Grilled Swordfish Steaks
• Grilled Octopus
• Rotisserie Chicken
• Homemade Roast Beef with Brown Onion Gravy

This tasty gratin is endlessly customizable. Here are just a few options:

• To make this mushroom casserole vegan, use dairy free butter to make the sauce and skip the cheese.
• Swap kale for spinach, escarole or other greens.
• Use cooked rice or a blend of brown and wild rice for the barley.
• Add small cubes of lightly steamed butternut squash to the gratin for extra color and nutrition.
• Add chunks of cooked chicken, pork or even browned ground beef to the casserole to make it a main course family dinner.
• Swap white wine or sherry for the vermouth, or skip the alcohol altogether.
• Use Emmentaler, Swiss, Comte or even white cheddar in place of the Gruyere.

FAQ’s

Other whole grain side dishes you might like:

• Mediterranean Chickpea Millet Salad
• Italian Wild Rice Salad
• Edamame Quinoa Salad
• Italian Bean Salad with Farro and Mozzarella
• Apple Quinoa Stuffed Acorn Squash
• Asian Rice Salad with Soy Ginger Dressing
• Warm Apple Butternut Farro
• Autumn Squash Risotto