The night before, put the cheese in a paper coffee filter set in a strainer over a bowl, cover with plastic wrap, and refrigerate. In the morning, discard the whey collected in the bowl. Process egg yolks and ricotta cheese in food processor or blender until smooth. Add milk, flour, sugar, baking powder, and salt and process until completely blended. Fold in lemon rind and lemon verbena. Beat egg whites in mixing bowl until just stiff but still moist. Fold gently into batter. Heat 2 teaspoons vegetable oil in large nonstick skillet over medium heat. Drop batter by quarter cupfuls onto skillet, and cook until tops are bubbly and look dry. Turn and cook second side until golden brown. Repeat with remaining batter. Serve immediately.