Preheat your oven to 350°F (175°C). Grease a 9x13-inch (23x33 cm) baking dish.
In a saucepan, combine the blueberries, sugar, vanilla extract, cornstarch, lemon zest, and water. Cook over medium heat, stirring occasionally, until the mixture thickens and the blueberries release their juices. Set aside.
In a bowl, whisk together flour, sugar, baking powder, and salt for the mini pancakes or blintzes.
In another bowl, whisk together milk, eggs, and melted butter. Add the wet ingredients to the dry ingredients and stir until just combined.
Heat a griddle or skillet over medium heat and lightly grease with butter or oil. Pour small amounts of batter to make mini pancakes or blintzes. Cook until bubbles form on the surface, then flip and cook the other side until golden brown. Repeat until all batter is used.
Arrange half of the mini pancakes or blintzes in the prepared baking dish. Spoon half of the blueberry mixture over them. Layer the remaining pancakes or blintzes on top and cover with the remaining blueberry mixture.
In a separate bowl, whisk together milk, heavy cream, sugar, eggs, vanilla extract, and a pinch of salt. Pour this soufflé mixture over the pancake and blueberry layers.
Bake in the preheated oven for 40-45 minutes or until the soufflé is set and golden brown.
Dust with powdered sugar before serving.
Enjoy this delicious blueberry blintz soufflé casserole with mini pancakes!