Grilled Chimichurri Portobello Burger with Smoked Cheese & Fried Onions

Prepare the chimichurri butter: combine soft butter, 1 tbsp chimichurri seasoning, the finely grated garlic, grated lemon zest, and a pinch of salt in a small bowl; mix until smooth.

Prepare the chimichurri sauce: whisk together mayonnaise, Greek yogurt, 1‑1.5 tbsp chimichurri seasoning, lemon juice, black pepper to taste, and a pinch of salt until fully incorporated.

Clean the portobello mushrooms, removing stems and gently wiping caps with a damp cloth.

Brush each mushroom lightly with neutral oil, then season both sides with pepper and salt to taste.

Preheat a grill or grill pan over medium‑high heat.

Grill the mushrooms for 4–5 minutes per side, until they develop a nice brown color and become tender.

Reduce the grill heat to low, brush the grilled mushrooms with the prepared chimichurri butter, and let it melt for about 1 minute.

Flip the mushrooms, brush the other side with more chimichurri butter, then place a slice of smoked cheese on each cap and cover the grill for another minute or until the cheese melts.

Slice the brioche buns horizontally. Lightly spread a thin layer of chimichurri butter on the cut sides of both the top and bottom halves.

Grill the bun halves, cut side down, for 1–2 minutes until they are golden and slightly crisp.

Assemble the burgers: spread a generous amount of chimichurri sauce on the bottom bun, add a handful of arugula, place the cheese‑topped portobello mushroom, add pickled red onion and fried onions to taste, then cap with the top bun.

Serve immediately while the buns are warm and the cheese is melty.