• Before you begin: Make the pickled mushrooms. You can make them ahead of time and store in your refrigerator for up to 3 months.

Roast the mushrooms

• Preheat the oven to 450°F. Toss the mushrooms with the vegetable oil and salt. Spread onto a parchment-lined baking sheet in a single layer, leaving space between the mushrooms. Roast for 10–18 minutes, shaking the pan once or twice, until browned and caramelized.
If doubling the recipe, be sure to divide the mushrooms between two parchment covered sheet pans. Mushrooms are made up of a lot of water, and high heat helps that water cook off before the mushrooms have a chance to steam. That's what gives you beautifully browned edges, a meaty texture, and the deep, concentrated flavor that makes roasted mushrooms so irresistible. Pair that with a little space between the mushrooms on the pan, and you'll be rewarded with mushrooms that are caramelized instead of rubbery.

Make the Vinaigrette

• Place the coriander, cumin, and peppercorns in a small dry skillet over low heat. Toast for 1–2 minutes until fragrant. Crush the warm spices using a mortar and pestle or spice grinder. In a large bowl, whisk together the crushed spices, grated garlic, cilantro, celery, celery leaves, sugar, vegetable oil, and balsamic vinegar.

Marinate the Roasted Mushrooms

• While the mushrooms are still warm, toss them with the vinaigrette. Let them marinate for about 1 hour, stirring once or twice.
While the mushrooms marinate, make a quick bruschetta with cherry tomatoes, basil, garlic, olive oil, and a pinch of salt. The fresh tomatoes are a delicious contrast to the rich mushrooms.

Assemble the Salad

• Fold the pickled mushrooms into the roasted mushrooms. Add 1–2 teaspoons of the pickling liquid if desired for extra brightness. Divide between two dinner plates or arrange on a serving platter. Top with sliced red onion and a generous dollop of Greek yogurt. Garnish with cilantro and freshly ground black pepper, if desired. Serve with toasted baguette or bruschetta.