Preheat the oven to 300℉. (To keep the pancakes warm)
Grate the zucchini into a bowl using the large side of a box grater. Immediately stir in the onion and eggs. Stir in 6 tablespoons of the flour, the baking powder, salt and pepper. (If the batter gets too thin from the liquid in the zucchini, add the remaining 2 tablespoons of flour.)
2 medium zucchini, grated, 2 tablespoons grated sweet onion, 2 large eggs, slightly beaten, 6 to 8 tablespoons flour, 1 teaspoon baking powder, 1 teaspoon salt, ½ teaspoon freshly ground black pepper
Heat a large (10 - 12 inch) saute pan over medium heat and melt 1/2 tablespoon butter and ½ tablespoon oil together in the pan. When the butter is hot but not smoking, lower heat to medium-low and drop heaping soup spoons of batter into the pan. Swirl the back of the spoon around the batter to even out the pancake. Cook the pancakes about 2 minutes on each side, until golden brown.
Unsalted butter and vegetable oil
If keeping the pancakes warm in the oven, place cooked pancakes on a baking sheet and keep warm in oven for up to 30 minutes.
Notes
Don't use olive oil here. Use a neutral oil like canola or vegetable oil.