Grilled Mushroom Sandwiches
It's not uncommon for my wife to come to me and shove her computer or phone in my face and simply declare, "Make me this," referring to whatever food is on the screen. That's how this grilled mushroom sandwich was brought to my attention after she saw it on Instagram. The inspirational sandwich is from a shop called Quinnie's in Hudson, NY and I've never been there, but this particular item really piqued my interest because I was having a hard time imagining how the disparate flavors would all come together—roasted mushrooms, walnuts, gremolata, and piquillo peppers all contained in hearty and chewy focaccia. So I really needed to try making it to find out.
A mushroom sandwich should rightfully start at mushrooms, and I've become a big fan of a mushroom medley when no one specific type is required. I did go in heavy with the criminis because they came in a large pack at a low cost, but I supplemented those with shitakes, king oyster, and oyster mushrooms. I find a variety like this helps build more flavor and texture that's really welcomed in the final dish.
I made a couple deviations from the inspirational sandwich, and one of those was to create a piquillo pepper mayo instead of using piquillo peppers straight up. In doing so, I was able to layer in a little more flavor that compliments the fruity piquillo by way of hot and smoked paprikas, which all got a whirl with the mayo base in a blender until smooth. The end result was a sauce that had a nice Spanish touch to it. It's not required, but making the mayo a little in advance can be helpful because it thins out in the blender, but thickens back up after sitting in the fridge for a bit.
What threw me the most in this this sandwich equation was how gremolata fit it. This minimal Italian condiment made of only lemon zest, parsley, and garlic is often used to bring a touch of freshness to heavier dishes or seafood, and I assumed it would serve the same purpose here, but couldn't quite envision how it would pair with the earthy mushrooms and piquillo peppers. I also wasn't sure how much gremolata went into each sandwich and erred on the heavier side to ensure its presence would be known.
I was about ready to switch up the bread too and use a ciabatta that my local bakery makes well, but I've honed my focaccia skills during the pandemic and I had some downtime a few days before I was going to make these sandwiches, so I started a batch of dough instead. Focaccia is a pretty minimal effort bread, you just need to plan ahead because it needs at least one day of cold fermentation, but two or three is even better. I use a recipe from Serious Eats that's written for a 12-inch cast iron skillet, but it works great in a 13x9-inch pan too, which gives you a shape more suitable for sandwich making.
There are multiple ways you could cook the mushrooms for this recipe—like sautéed in some butter in pan or roasted in the oven—but this is a grilling site, so you can be sure I did them up over a live fire. Beyond the slight flavor enhancement a grill provides, the high heat and large surface area meant I was able to cook all the mushrooms in one fell swoop in just under ten minutes.
Once they were done, I transferred them to a cutting board and roughly chopped them. I wanted to some nice sized chunks to give this primary sandwich filler heft and a variety of textures.
To assemble the sandwiches I spread a layer of mayo on each side of the bread and topped the bottom half with mushrooms and chopped pistachios. The nut of choice was another change-up I made partly because I like pistachios better, and partly because I have a comically large bag of them I need to work through, so they just end up being my go-to nut more often than not these days. Following that went on the gremolata and I actually put the assembled sandwiches back on the grill for a bit to warm up because enough time had passed from when I chopped the mushroom until I assembled that sandwiches that I felt additional heating was warranted.
Even after all that work, it wasn't until I had a few bites that I fully understood how everything worked together. The mushrooms proved to be a hearty base and provided a rich and earthy start that was well paired with the smoky and fruity piquillo mayo that also lent a minimal heat as well. As expected, the gremolata injected those two heavier flavors with a touch of freshness by way of the lemon and parsley, while the garlic added a little sharpness that was at home with the overall flavor profile. The pistachios most notably added an important crunch to the otherwise soft and chewy texture that was defined most by the focaccia, whose heartiness I felt was really key in making this sandwich feel meal-worthy. So I can mark this as a win for my wife, who brings me recipe ideas that have challenged me and also delivered time and again.
