Preheat oven to 200 degrees. Have a baking sheet ready.

Trim ends off zucchini and grate them either on the large holes of a box grater or using the shredding blade of a food processor.

In a large bowl, toss zucchini with 1 teaspoon coarse salt and set aside for 10 minutes.

Wring out the zucchini to extract the water using a colander, squeezing out small handfuls, or wrapping it in a clean dishtowel.

Return deflated mass of zucchini shreds to bowl. Taste and add more salt if needed.

Stir in scallions, egg, and freshly ground black pepper.

In a tiny dish, stir together flour and baking powder, then stir the mixture into the zucchini batter.

In a large heavy skillet, heat 2 tablespoons of oil over medium-high heat until shimmering.

Drop small bunches of the zucchini mixture onto the skillet and lightly nudge them flatter with the back of your spatula.

Cook the fritters over moderately high heat until the edges underneath are golden, about 3 to 4 minutes.

Flip the fritters and fry them on the other side until browned underneath again, about 2 to 3 minutes more.

Drain briefly on paper towels then transfer to baking sheet and into the warm oven until needed.

For the topping, stir together the sour cream, lemon juice, zest, salt, and garlic and adjust the flavors to your taste.

Dollop on each fritter before serving.