Step 1

Position racks in center and upper third of oven; preheat to 425 degrees F.

Step 2

Combine 1 tablespoon oil, lemon zest, lemon juice, oregano and 1/4 teaspoon pepper in a small bowl. Add halloumi and stir to coat; set aside.

Step 3

Toss potatoes and green beans with 1 tablespoon oil, 1/8 teaspoon salt and the remaining 1/4 teaspoon pepper on a large rimmed baking sheet. Spread in a single layer. Roast on the center rack for 10 minutes. Scatter tomatoes over the vegetables and continue roasting until the potatoes are tender and the tomatoes are wilted, 5 to 10 minutes more. Transfer to a large bowl.

Step 4

Turn the broiler to high. Using a slotted spoon, transfer the reserved halloumi to the baking sheet (reserve the marinade). Broil, stirring once, until lightly browned, 3 to 5 minutes.

Step 5

Meanwhile, heat the remaining 2 tablespoons oil and garlic in a small saucepan over medium heat until the garlic begins to sizzle, then cook for 15 seconds. Remove from heat and whisk in vinegar, the reserved marinade and the remaining 1/8 teaspoon salt.

Step 6

Add escarole to the vegetables and gently toss with the warm dressing to combine. Serve topped with the halloumi and hazelnuts.