In a medium bowl, combine the plain Greek yogurt, minced garlic, lemon juice and zest, salt, and pepper. Stir until smooth and creamy.

On a cutting board, gently smash each zucchini using a rolling pin or meat mallet until they split into large pieces, about 1-inch thick.

Transfer the smashed zucchini to a large bowl and drizzle with olive oil, salt, and pepper. Toss until evenly coated.

Preheat your broiler to high (around 550°F). Arrange the zucchini on a baking sheet and broil for 5 to 7 minutes, checking frequently.

Remove from the oven and spread the garlic yogurt sauce on a serving platter. Top with broiled zucchini, garnishing with pecorino romano and red pepper flakes.