Preheat your oven to 180°C or fan forced 160°C. This ensures an even cooking temperature for all the ingredients.
Roughly chop the onions and capsicums into bite-sized pieces. The goal is to have them cook evenly and blend well with the other ingredients.
In a large, shallow casserole dish that can go from hob to oven, heat the olive oil over medium heat. Add the chopped onions and capsicum, cooking them until they soften and start to take on a beautiful golden hue, which should take about 5 minutes.
While the vegetables are cooking, slice the garlic and add it to the onion mixture. Sauté for a minute until the garlic becomes fragrant but be careful not to let it brown.
Stir in the Greek seasoning and pour in the chopped tomatoes. To ensure you don’t waste any tomato goodness, fill the empty can with about ⅓ can of water and swish it around, then add this to the pan.
Stir everything together until combined, then let it simmer on low heat until it begins to bubble gently.
While the sauce is simmering, lay the chicken thighs on a plate. Drizzle them with a bit of olive oil and rub in some remaining Greek seasoning to coat each piece well.
Once the sauce is gently simmering, carefully add the seasoned chicken thighs in a single layer. This allows them to soak in all those wonderful flavors.
Cover the dish with a lid or aluminum foil and place it in the oven. Bake for 30 minutes to let the flavors meld beautifully.
After 30 minutes, remove the lid or foil and bake uncovered for an additional 10 minutes. This allows the top to brown nicely and the sauce to thicken, creating a delicious crust on the chicken.
Once done, serve the dish warm, garnished with chopped oregano, black olives, and generous crumbles of feta cheese. Enjoy!