Whenever I'm looking for a side dish to pair with steak, my mind tends to gravitate toward mushrooms, since the two are such a fantastic pair. The only problem is a visual one: both are brown, making for a monochromatic dish. Steakhouses solve this problem by adding a completely unnecessary sprig of parsley, but I decided to go all in and add as much green as possible. That's how I ended up with the idea of a pesto.
Well, at least for a while. The sauce started out as a chunky, oily pesto, albeit one made with pumpkin seeds and cilantro instead of pine nuts and basil. But I also wanted it to have some zing, so I squeezed some lime juice in. Turns out, the more lime juice I added in the more I liked it, making this more like a salsa than anything else (without any chilies, of course). Since the pumpkin seeds are toasted first, they have a smoky, roasted aroma, which is cut by the freshness of the cilantro and lime. It's great stuff.
Because the sauce is so flavorful, I didn't want to do anything to the steak except season it well and cook it to medium-rare. While grilling would be a fantastic option for the summer, that's not a convenient weekday option for me. Instead, I just cooked it in my heavy cast-iron skillet for about eight minutes. Just remember to slice the flank steak against the grain.
I took the same approach with the mushrooms, simply tossing them in the skillet once the steak was done. Once they release their water, you can scrape up any browned bits leftover from the steak, so the 'shrooms come out meaty, smoky, and tender.
- Yield:Serves 4
- Active time: 20 minutes
- Total time:20 minutes
- 1/2 cup pumpkin seeds
- 3/4 cup fresh cilantro leaves
- 1 medium garlic clove, chopped (about 1 teaspoon)
- 1/2 cup olive oil
- 3 to 4 tablespoons fresh juice from 3 to 4 limes
- Kosher salt and freshly ground black pepper
- 1 pound flank steak
- 2 tablespoons canola oil
- 8 ounces shiitake mushrooms, wiped clean, ends trimmed
Heat a large 12-inch cast-iron skillet over medium heat. Add pumpkin seeds and toast, stirring often with a wooden spoon, until lightly browned, but not burnt. Transfer pumpkin seeds to a blender, turn off the heat, and wipe out the skillet.
Add cilantro, garlic, and olive oil to the blender and process until pumpkin seeds are well chopped. Transfer to a medium bowl and add 3 tablespoons of lime juice and season to taste with salt and pepper. Taste, and add another tablespoon of lime juice if necessary.
Season flank steak with a generous pinch of salt and pepper on both sides. Heat canola oil in the cast-iron skillet over medium-high heat until shimmering. Carefully set steak in the skillet and cook, flipping every 2 minutes, until browned on the outside and center registers 130°F on an instant-read thermometer for medium-rare, about 8 minutes total. Transfer steak to a large plate and let rest.
Once skillet has cooled slightly, remove all but 1 tablespoon of fat in the skillet, and turn heat to medium. Add the mushrooms and stir well. Cook, stirring often and scraping up any browned bits, until mushrooms have released their water and are tender, about 8 minutes. Season to taste with salt and pepper.
Slice flank steak thinly against the grain. Spoon some of the pesto onto a plate and top with the slices of steak. Serve immediately with mushrooms.