Preheat oven to 425 degrees. Line a baking sheet with foil or parchment paper.
In a bowl, mix together onion powder, garlic powder, and pepper. Add the halloumi to the mixture and toss together.
Place halloumi on the prepared baking sheet in a single layer. Drizzle halloumi with oil.
Bake for 10 minutes then flip and bake another 10 minutes until golden and crisp.
Serve with dipping sauce.