Preheat the oven to 450℉. Line a large, rimmed baking sheet with foil or high-heat-resistant parchment paper.
Rinse the okra and dry it on a clean kitchen towel or paper towels. Trim the ends if you wish (this is not mandatory and I usually don't).
Place the okra in a large bowl and toss with the olive oil, salt, pepper, and garlic powder.
Arrange the okra in a single layer on the prepared baking sheet.
Roast the okra until lightly browned and tender, about 20 minutes, stirring halfway through baking.
While the okra is in the oven, mix the dipping sauce ingredients (mayonnaise, Dijon mustard, and hot sauce) if you plan on using it.
Serve the okra with or without the dipping sauce.
Video
Notes
The nutrition info does not include the optional dipping sauce.
To improve the okra's texture and remove its slime, you should roast it at very high heat, so set your oven to 450°F. In many recipes, you can play a little with the oven temperature, but here, I highly recommend sticking with a truly hot oven.
If you prefer an oil with a high smoke point, use avocado oil.
You can keep the leftovers in an airtight container in the fridge for 3-4 days. Reheat them uncovered in a 350°F oven. They are also delicious when served cold, antipasti style.