Steps
1. Preheat the oven to 375 degrees F.
2. Slice the onion into thin, half-moon shapes.
3. Heat the olive oil in a skillet over medium heat.
4. Add the onion slices and sauté, stirring occasionally, for about 10 minutes, or until tender and beginning to caramelize.
5. Sprinkle over salt and sugar. Stir and cook for another 2 minutes.
6. Remove from heat and let cool slightly.
7. Place the pre-made frozen pie crust on a baking sheet, and arrange the caramelized onions on top.
8. Bake in preheated oven for 15 minutes or until golden brown.
9. Allow to cool for 10 minutes before serving.