To make the chimichurri, pick the leaves and tender stems from the mint, cilantro, and parsley (discard tougher stems). Reserve half of the herb leaves for the herb salad. Finely chop mint (about ½ cup chopped), cilantro (about 6 Tbsp. chopped), and parsley (about ½ cup chopped) along with all the radish greens (about ½ cup chopped).

Add the chopped herbs to a large bowl with garlic, shallot, and jalapeño and mix to combine. Add vinegar, crushed red pepper flakes and mix well. Add oil, stirring with a fork to combine. The chimichurri should be loose and able to be drizzled with a spoon. Taste and season with salt and pepper. Chill until ready to use; makes about 3 cups.

Slice the oyster mushrooms into 1”-thick steaks, keeping part of the root attached for easier grilling. Brush one side with a little grapeseed oil and season generously with salt and lightly with pepper.

Heat a Grill Frying Pan on the grill (or a Griddle on a stovetop) over medium-high until hot, 3–5 minutes. Lightly oil cooking surface and sear the mushrooms (oiled-side down) until browned, 4–5 minutes. Brush the other side of mushrooms with oil, season with salt and pepper, and flip. Cook until crispy on the outside and tender on the inside, 4–5 minutes more.

Place grilled mushrooms on a Serving Platter and drizzle 1–2 tablespoons chimichurri over each mushroom “steak.”

Add the arugula, reserved minced herbs, and sliced radishes to a large bowl. Drizzle a few spoonfuls of the chimichurri onto the salad and toss to combine. Add to platter alongside grilled mushrooms and serve.