This stew is so delicious I swear I could eat it every day for the rest of my life. Since it's exactly the kind of umami-forward dish I would (and have) put together on my own during autumns past, I struggled with whether to adapt Deb Perelman's recipe from Smitten Kitchen. But this version, with my own adaptations, is just right, so I went for it. I also wanted to introduce you to the cookbook in which I first noticed the recipe, Food52's Genius Recipes. More on this book in time for holiday gifting.
In a 12-inch, heavy nonstick skillet,** heat one tablespoon each of the olive oil and butter over high heat. Add half the sliced mushrooms and cook without disturbing until golden brown on one side, about 3 minutes. Toss once and cook until some mushrooms start to brown on the other side (don't stress at all about flipping all of them perfectly), about two minutes more. Scrape into a large bowl and repeat with a second tablespoon each of olive oil and butter and the other half of the mushrooms. Set mushrooms aside.
In the same skillet, warm the remaining tablespoon olive oil over medium-high heat. Add onion and carrot along with 1/2 teaspoon salt and a few grinds black pepper and cook, stirring occasionally, for 10 minutes, Onions and carrots should be lightly browned. Stir in the garlic, thyme (stems and all) and sage and cook until very fragrant, a minute or two.
Pour in the wine. Turn heat up to high and simmer briskly until reduced by half. Stir in tomato paste and broth, then add back the mushrooms and all the beautiful accumulated juice from the bowl. If your broth is low-sodium, add an additional 1/2 teaspoon salt. If not, wait and taste at the end. Bring to a boil, then simmer for 20 minutes. (This is a good time to start the mashed potatoes.)
With a fork, thoroughly mash together the remaining tablespoon of butter and the flour in a small bowl to form a paste. Stir paste into stew. Lower heat to simmer gently and cook 10 minutes more. Sauce should be thick and glossy. Taste for salt and pepper. Remove or avoid thyme stems. Serve spooned over mashed potatoes.
* I would normally use a very full-bodied wine for a recipe like this, but most recently I added the Pinot Noir I was drinking, which is quite a bit lighter, and it worked beautifully. So as long as you're using a good red wine that you like to drink, it's allllll goooood.
**I've become obsessed with these eco-friendly, chemical-free pans in the past couple of years, by the by.
*** To make this recipe gluten-free, substitute a gluten-free flour blend.