1. Grate zucchini into a medium or large bowl. Blot with paper towel to remove some moisture.
2. Add finely chopped scallions, garlic, egg and flour. Season with salt and pepper. Stir well to distribute ingredients evenly.
3. Heat olive oil in a large skillet over medium-high heat. Drop rounded spoonfuls of zucchini batter into hot oil, flattening slightly to form a pancake. Fry in batches until golden, about 3 minutes per side.
4. Drain pancakes on a paper towel-lined plate to remove excess oil. Serve with sour cream.