Preheat oven to 350 degrees F.
Heat a saute pan over medium heat. Add oil, swirl pan, then add onion and a pinch of salt. Cook for 6-7 minutes, stirring a few times, until onion is translucent and has shrunk a bit. Then add garlic and spinach, and saute for 2 to 3 more minutes, until spinach is mostly wilted. Remove pan from heat and move the mixture into a large bowl to cool a few minutes.
Now you'll use a blender. Add eggs, cottage cheese, cream, cornstarch, salt, and pepper. Blend until smooth.
Pour into the bowl with the spinach mixture, and add sun-dried tomatoes, 3 ounces feta cheese that you crumble lightly while it's going into bowl, and fresh dill.
Grease a 7x11 OR 9x9 inch pan (do not use glass, they don't cook evenly). Add potatoes to pan in a single layer. Then pour egg and veggie mixture evenly over potatoes. Finish with remaining 1 ounce of feta cheese, crumbling lightly onto top.
Bake for 45-50 minutes, until eggs are set. I test this by poking a toothpick into the center and making sure it is not liquid-y, but just cooked through. Let cool 5 to 10 minutes before serving, then serve each slice with minced fresh dill.