Multigrain Pancakes

From Cook’s Illustrated

4 teaspoons fresh lemon juice
2 cups whole milk
1 ¼ cups no-sugar-added muesli , plus an additional 3 tablespoons
¾ cup unbleached all-purpose flour
½ cup whole wheat flour
2 tablespoons brown sugar
2¼ teaspoons baking powder
½ teaspoon baking soda
½ teaspoon sea salt
2 large eggs
3 tablespoons unsalted butter, melted and cooled
¾ teaspoon vanilla extract
Vegetable oil

1. Whisk lemon juice and milk together in medium bowl or 4-cup measuring cup; set aside to thicken while preparing other ingredients.
2. Process 1 ¼ cups muesli in food processor until finely ground; transfer to large bowl. Add remaining 3 tablespoons unground muesli, flours, brown sugar, baking powder, baking soda, and salt; whisk to combine.
3. Whisk eggs, melted butter, and vanilla into milk until combined. Make well in center of dry ingredients in bowl; pour in milk mixture and whisk very gently until just combined (few streaks of flour and lumps should remain). Do not overmix. Allow batter to sit while pan heats.
4. Heat 12-inch cast iron skillet over medium-low heat for 5 minutes. Add vegetable oil. Pour ¼ cup batter onto 3 spots in skillet, using bottom of ladle to spread batter smooth if necessary. Cook pancakes until small bubbles begin to appear evenly over surface, 2 to 3 minutes. Using thin, wide spatula, flip pancakes and cook until golden brown on second side, 1 ½ to 2 minutes longer. Serve immediately. Repeat with remaining batter, adding more oil as necessary between batches and adjusting heat if necessary.