1. Place potatoes in a large pot with enough water to cover. Add one tablespoon salt and bring to a boil. Lower heat and simmer until potatoes are very soft, about 20 minutes.
2. Drain potatoes and mash well, using a potato masher, until no lumps remain. Refrigerate until cooled, about one hour.
3. While potatoes are cooling, line a colander with several pieces of paper towel. Place spinach onto the paper towels. Cover with an additional paper towel and squeeze out any excess liquid.
4. Pack tightly into a half-cup measure. Mix diced pepper with one teaspoon oil and sprinkle lightly with salt. Set aside.
5. Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius). Line two baking pans with Gefen Parchment Paper.
6. Add spinach, oil, eggs, potato starch, garlic powder, and additional salt to taste to cold potatoes and mix very well until combined.
7. Using a three-tablespoon ice cream scoop, place about 24 scoops of potato mixture onto the parchment paper, spacing them evenly apart. Using a pastry brush, brush each scoop with beaten egg.
8. Using the tip of a pointed teaspoon, create a 1/2-inch (one centimeter) deep by 1/2-inch (one centimeter) wide indentation in the center of each scoop. To prevent sticking, dip the tip of the spoon into the beaten egg before pushing it into each potato scoop.
9. Place about 1/2 teaspoon diced peppers into each indentation.
10. Bake uncovered for 35–40 minutes or until edges begin to brown slightly. Serve warm.