Halve then grate the inside of the tomato so that you are left with the skin and any firm core - discard the skin/core. Alternatively, if you prefer a slightly coarser texture, just dice the tomato relatively small (remove or leave the skin to taste first). Finely chop the garlic.
Crack the eggs into a small bowl, add the salt and pepper and whisk until well broken up and gently bubbly.
Warm the oil in a small skillet over a medium heat then add the tomatoes, garlic and oregano. Cook for around 3 - 5 minutes so that the tomatoes are soft, cooked and the sauce thickens a little.
Reduce the heat to medium-low and add the egg - if you prefer the egg pieces more separated, push the tomatoes to one side first and cook the eggs on the other, but more typically you just add into the tomato sauce and let the sauce cook them and for it all to mix. Stir the eggs as they cook and remove from the heat as they are almost cooked through - remember they will continue to cook a little off the heat. Serve topped with the crumbled feta (or you can mix it through off the heat, if you prefer).