Method
1. Bring water to boil in a clean large saucepan
2. Add potato and cook until tender
3. Drain, slice lengthwise then set aside
4. Grease a clean ceramic baking dish with olive oil
5. Line with parchment paper
6. Add olive oil, onion and chorizo to a clean medium cast iron skillet
7. Fry until softened - 5 min, medium heat
8. Add egg, milk and salt & pepper to a clean large mixing bowl and beat until completely mixed
9. Mix in roasted red pepper and fried chorizo
10. Add sliced potatoes and transfer mixture to ceramic baking dish
11. Cover ceramic baking dish with foil
12. Put the baking dish inside of the slow cooker bowl
13. Pour water into the slow cooker bowl halfway
14. Cook tortilla until set - 2 hr 30 min, high heat
15. Lift dish out of the slow cooker pot using a dish towel and remove the foil
16. Loosen the edge of the tortilla with a knife and turn on a serving plate
17. Slice and serve