Preheat the oven to 190 degrees Celsius. Rinse the red, yellow and orange peppers, halve them lengthwise and carefully remove the seeds and membranes. Finely mince the garlic cloves and halve the cherry tomatoes.
Heat a splash of olive oil in a frying pan over medium-high heat and crumble the ground beef until cooked. Add the finely minced garlic and tomato paste and cook briefly. Mix the cherry tomatoes, oregano, thyme, pepper and salt through the meat and simmer gently for a few more minutes.
Place the empty pepper halves side by side in a suitable baking dish. Spoon the warm meat mixture into the peppers and fill them to the top. Crumble the feta cheese and sprinkle it evenly over the six filled halves.
Slide the baking dish into the preheated oven and bake the dish for 25 minutes until cooked through. Remove the dish from the oven once the peppers are soft and the cheese has melted. Serve the stuffed peppers immediately while still hot.