Grease a 9x13-inch baking dish with butter.
Cut pancakes in half and layer in baking dish cut side down.
Distribute half of the blueberries in with the pancakes as you put them in place.
Whisk together eggs, milk, cream, sugar and vanilla.
Pour mixture over the pancakes (insure all get wet).
Spread the remaining blueberries over the top of pancakes.
Combine the flour, sugar, cinnamon and salt.
Cut the butter into the other ingredients with a fork to make a course crumble topping.
Sprinkle over the pancakes.
Allow to soak in the fridge for at least 2 hours.
Preheat oven to 350.
Bake for about 1 hour, until browned and centre is set up.
Allow to cool for 15 minutes.
Dust with powdered sugar before serving.