Cut the chicken breast into even, bite-sized cubes and slice the onion into strips. Keeping pieces uniform helps everything cook at the same rate.

In a large bowl, combine the olive oil with all the spices and mix until they form a loose paste.

Add the cubed chicken and sliced onion to the bowl. Toss everything together until every piece is fully coated. Cover and refrigerate for at least 4 hours, or overnight for best flavor.

When ready to cook, preheat your oven to 450 degrees F. Line a baking sheet with parchment paper.

Spread the marinated chicken and onions in a single layer on the prepared sheet pan. Do not overcrowd; overlapping pieces will steam instead of roast.

Roast for 20 to 25 minutes until the chicken reaches an internal temperature of 165 degrees F. For crispy edges, switch the broiler on for the last 2 minutes. Watch closely so nothing burns.