Wash the zucchini thoroughly and remove both ends. Shred it using the coarse side of a box grater or the grating attachment of a food processor.

Place the grated zucchini in a large bowl and mix it with 1 teaspoon of the fine sea salt. Allow the mixture to rest for 10 minutes so the salt can draw out the excess moisture.

Working in handfuls, firmly squeeze the zucchini over the sink to extract as much liquid as possible. A clean cheesecloth may also be used to wring it more thoroughly. The drained zucchini should yield approximately 3½ to 4 cups.

Transfer the well-drained zucchini to a clean mixing bowl. Add the beaten eggs and chopped scallions, then stir until the ingredients are evenly distributed.

In a separate small bowl, whisk together the flour, baking powder, black pepper, and the remaining ½ teaspoon of sea salt.

Pour the dry ingredients into the zucchini mixture. Stir only until everything is incorporated and a consistent batter has formed.

Set a large cast-iron or nonstick skillet over medium heat. Pour in enough olive oil to cover the base of the pan, beginning with approximately 2 tablespoons.

When the oil is hot, spoon heaping tablespoons of batter into the skillet. Lightly press each portion with the back of the spoon to create an even, pancake-like shape.

Cook the fritters for 3 to 5 minutes on each side, turning once, until the surfaces are crisp and richly golden. Reduce the heat if the exterior begins browning before the center is fully cooked.

Transfer the finished zucchini fritters to a serving plate. Serve them warm with a generous spoonful of sour cream on top or alongside for dipping.