In a medium bowl, stir together 1 cup milk and 1 tablespoon lemon juice. Let sit about 10 minutes.
After 10 minutes, whisk into the milk mixture: 1/2 cup (4 ounces) whole milk blueberry yogurt (or vanilla yogurt), 2 teaspoons lemon zest, 1 teaspoon vanilla, 1 egg, and 2 tablespoons melted unsalted butter.
In a large bowl, whisk together the dry ingredients: 1/2 cup whole wheat flour and 1/2 cup all-purpose flour, 2 tablespoons sugar, 1 teaspoon baking powder, 1/2 teaspoon baking soda, and 1/4 teaspoon salt. OR measure 1 1/4 cups homemade whole wheat pancake mix and use that in place of the two flours plus the sugar, baking powder, baking soda, and salt.
Pour the wet ingredients into the dry ingredients and stir gently until just combined; do not overmix—the batter should be slightly lumpy.
Fold in 1/2 cup fresh or frozen blueberries gently so they are evenly distributed.
Heat a non-stick griddle or large frying pan over medium heat. If the surface is not non-stick, lightly grease it with a little of the melted butter.
Using a 1/3-cup measure, pour batter onto the hot griddle or pan, leaving space between pancakes. Cook until the edges look set and bubbles form and begin to pop on the surface, about 1–2 minutes.
Flip each pancake and cook the other side until golden brown and cooked through, about 1–2 minutes more. If using frozen blueberries, allow a bit more time on the second side for the berries to warm through.
Transfer cooked pancakes to a plate and keep warm while you finish the rest. Serve warm, topped with additional butter and extra blueberries if desired.