Rinse the tomato and cut it into small cubes. Break the three eggs into a bowl and beat them well with a fork. Season the egg mixture immediately with a pinch of salt and some pepper and set it aside.
Heat the tablespoon of olive oil in a skillet over medium-high heat. Add the tomato cubes and the two handfuls of spinach to the pan. Sear briefly until the spinach just begins to wilt. Then pour the beaten egg mixture evenly over the vegetables in the pan.
Turn the heat down slightly and let the omelet set gently. Wait until the top of the egg is almost completely set. Crumble the forty grams of goat cheese over one half of the omelet and fold the other half over it neatly with a spatula.
Let the folded omelet sit in the warm pan for another half minute so the goat cheese can melt slightly. Then slide the omelet directly from the pan onto a plate and serve right away.