Mix all the ingredients until well combined, then shape the dough into a round ball. Cover with plastic wrap and refrigerate for 30 minutes.
Preheat oven to 338°F (170°C).
Roll out the dough with a rolling pin until it reaches a diameter of 18 cm. Gently press the dough into a removable pie pan, ensuring it covers all surfaces.
Gently press the pie dough down so that it lines the bottom and sides of the pie plate, cut out the excess. Poke the bottom of the crust with a fork. Carefully place an aluminum foil and gently press it to the pie dough and place rice on top of it to prevent the pie from rising in the center.
Bake 350°F (170°C) for 30 minutes.
In a pan, saute garlic and onion over medium heat until fragrant. Add smoked beef, tomato, and spinach. Stir and cook for awhile. Add salt, black pepper, and sugar. Stir well and set aside.
Mix all the ingredients until well combined.
Preheat oven at 180℃
Spread the spinach mixture onto the pie crust, then pour the egg custard mixture until it reaches a slightly full surface.
Bake the creamy spinach quiche for 30 minutes or until the custard sets. Serve while the pie is still hot. Enjoy!