1. Heat olive oil in a medium frying pan and sauté onions for approximately 10 minutes.
2. Add pastrami and cook for an additional minute.
3. Remove from heat, and transfer to a mixing bowl and allow to cool.
4. Once the onion-pastrami mixture is cool, stir in eggs and soy milk.
5. Mix well.
6. Spoon mixture into mini tart shells.
7. Preheat oven to 350 degrees Fahrenheit (180 degrees Celsius), and bake mini tartlets for 30 minutes.