Make a tart crust by combining the flour, the fresh thyme, and salt in a food processor.
With the machine running, add the water and olive oil in a continuous stream. Continue processing until a soft dough forms.
Cover with plastic and refrigerate for about 30 minutes.
Preheat the oven to 400 F.
Saute the onions over medium heat in the 2 tablespoons of olive oil. Add the lettuce and sauté until it wilts and most of the liquid is evaporated.
Place the lettuce mixture in a bowl and add the thyme, the eggs, and the sour cream. Mix thoroughly.
Roll or pat the dough into a circle about 12 inches across. Crimp the edges to form a crust and spread the lettuce mixture over the top. Smooth it to even it out.
Sprinkle the pitted olives over the lettuce.
Bake for about 30 minutes.
This is delicious warm or cold. If served cold, it's excellent with fresh fruit and crusty bread.