Baked Eggplant with Tomato & Feta (Gluten-Free)



1 eggplant/aubergine, sliced in half lengthwise and scored all over in a criss-cross pattern (without cutting through the skin).
a little olive oil for baking
feta cheese (about 80 grams/3 ounces)

for the tomato sauce:

about ¼ cup olive oil
5 or 6 cloves of garlic, sliced
1 x 400 gram/14 ounce can chopped tomatoes
a big sprig or two of a fresh herb e.g. basil (optional)
1 teaspoon salt & a good few grindings of pepper
1 teaspoon sugar & a drizzle of balsamic vinegar