Wash zucchini and trim off ends. Grate on the large holes of a box grater or use the grater attachment for the food processor. Place zucchini in a large mixing bowl, stir in 1 tsp salt, and set aside for 10 minutes.
After 10 minutes, squeeze handfuls of zucchini tightly over the sink to remove extra water. It helps to wring it out in a cheesecloth if you have one. You should end up with 3.5 to 4 cups of squeezed dry zucchini. Transfer to a large mixing bowl.
Add 1/2 cups chopped green onion and 2 lightly beaten eggs.
In a small bowl, stir together 3/4 cup flour with 1 tsp baking powder, 1/2 tsp salt, and 1/2 tsp black pepper, or season to taste. Add flour mixture into zucchini mixture and stir until well combined.
Place a large heavy-bottomed cast iron or non-stick skillet over medium heat and add 2 Tbsp olive oil. Once the oil is hot, add the zucchini mixture a heaping tablespoon at a time and flatten out the tops slightly to make them pancake-shaped.
Sauté for 3 to 5 minutes per side or until golden brown. If they brown too quickly, reduce the heat. Serve warm with a dollop of sour cream.
