First, preheat the oven to 425ºF.
Then, prepare red potatoes by washing and patting them dry. Then quarter them and place them on a baking sheet.
Finely dice the onion and add to the baking sheet and toss with potatoes.
Next, prepare spice rub by combining garlic powder, oregano, chili powder, salt, and pepper in a small bowl and mix.
Drizzle a generous amount of olive oil (2-3 tablespoons) over potatoes and onions and toss until fully coated.
Sprinkle seasoning mixture over potatoes and onions and toss together making sure all potatoes are covered.
Roast at 425ºF for 30-40 minutes. Toss after 15 minutes, and again at 30 minutes. Depending on the size of the potatoes, an additional 10 minutes may be necessary. You know your potatoes are done cooking when they are crispy and golden brown on the outside and soft on the inside.