01 - Grease a 9 x 13 inch baking dish thoroughly. Spread half of the bread cubes in an even layer across the bottom.
02 - Scatter cream cheese cubes and half the blueberries evenly over the bread. Top with remaining bread cubes and blueberries, distributing them uniformly.
03 - In a mixing bowl, whisk together eggs, milk, cream, sugar, and vanilla extract until fully combined and smooth. Pour the mixture evenly over the bread and berries, pressing gently to ensure all bread pieces absorb the liquid.
04 - Cover the dish and refrigerate for at least 30 minutes, or overnight for optimal results and enhanced flavor development.
05 - Preheat oven to 350°F.
06 - In a small bowl, combine softened butter, brown sugar, flour, cinnamon, and salt. Mix with a fork until the mixture reaches a crumbly, sand-like texture.
07 - Sprinkle streusel evenly over the casserole. Bake uncovered for 40 to 45 minutes until golden brown and set in the center.
08 - Cool slightly before serving. Dust with powdered sugar if desired.