How to Make It
In a colander set in the sink, toss the zucchini with 1 teaspoon of salt; let drain for 20 minutes. Squeeze the zucchini, a handful at a time, to remove as much liquid as possible.
Meanwhile, heat the olive oil in a medium skillet until shimmering. Add the onion and cook over moderately high heat, stirring, until softened, about 5 minutes. Transfer to a plate to cool.
In a medium bowl, sift the flour with the baking powder, 1 teaspoon of salt and 1/4 teaspoon of ground pepper. Add the zucchini, onion, milk and egg and stir until smooth. Let the batter rest at room temperature for 20 minutes.
In a medium skillet, heat 3/4 inch of vegetable oil until shimmering. Pat the capers dry with paper towels. Add them to the oil and fry until crisp, about 4 minutes. Using a slotted spoon, transfer the capers to paper towels to drain.
Scoop scant tablespoonfuls of the fritter batter into the hot oil, without crowding, and fry until crisp and golden all over, about 2 minutes per side. Drain the fritters on paper towels and sprinkle with salt. Top each fritter with a scant teaspoon of crème fraîche and a few fried capers and serve right away.