I start by slicing the halloumi into even ¼-inch pieces so they cook consistently. Then I cut the peaches into quarters and remove the pits, slicing around them if they're stubborn. Having everything cut and ready before the grill heats up saves me from rushing later.
In a small bowl or jar, I whisk the honey, lemon juice, salt, pepper, and olive oil until it's fully emulsified. I love making this in a mason jar because I can just shake it instead of whisking by hand. I set it aside while the grill heats up.
Next, I generously coat both the halloumi and the peach quarters with olive oil on all sides. A little salt and pepper goes a long way here, helping the natural flavors really shine once they hit the heat.
I preheat my grill to high and make sure the grates are spotless and well-oiled. This step matters more than people realize, since sticky grates will tear apart your delicate cheese and fruit slices in seconds.
I place the peaches cut-side down and the halloumi slices on the grill, then lower the heat to medium-high without closing the lid. I watch closely so nothing burns, since this part goes fast.
Once the peaches show nice grill marks, I flip them to char the other side lightly, keeping their texture intact. I flip the halloumi once it browns underneath, letting it get as crispy as I personally like.
I toss the arugula and jalapeño slices with most of the dressing, then plate it up. I arrange the warm halloumi and peaches on top and finish with a final drizzle of vinaigrette before serving right away.