Prepare the Peppers: Carefully slice a T-shaped incision into each pepper, being cautious not to split them completely. Gently open them up and remove the seeds, keeping the rest of the pepper intact. Wash thoroughly under running water to clean.
Prepare the Stuffing: In a mixing bowl, crumble the feta cheese finely. Add the grated kefalograviera cheese, Greek yoghurt, finely chopped spring onions, finely chopped parsley, minced garlic, diced tomato, dried mint, dried oregano, and black pepper. Mix everything together well until fully combined.
Stuff the Peppers: Using a large spoon, fill each pepper generously with the stuffing. Use a small spoon to gently push the mixture down to fill the bottom and sides of the pepper completely.
Arrange for Baking: Place the stuffed peppers snugly into a baking dish to help them stay upright.
Add the Topping: Drizzle a little olive oil over the stuffed peppers. Sprinkle the pepper skins with salt to taste. Top with extra kefalograviera cheese for a crispy, golden finish.
Bake: Insert the peppers into a preheated oven at 180°C (fan-forced) and bake for approximately 45 minutes, or until the peppers are slightly charred and cooked through.
Rest and Serve: Remove the peppers from the oven and allow them to rest for 5-10 minutes before serving.
Enjoy: Garnish with some extra slices of spring onion greens for added presentation and serve warm.