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 remaining blueberries.
03 - In a mixing bowl, whisk together eggs, milk, cream, sugar, and vanilla extract until fully combined.
04 - Pour the custard mixture evenly over the bread and berries. Press gently with a spatula to ensure all bread pieces absorb the liquid. Cover and refrigerate for at least 30 minutes, or overnight for optimal results.
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 mixture becomes crumbly.
07 - Sprinkle streusel mixture evenly over the entire casserole surface.
08 - Bake uncovered for 40 to 45 minutes until golden brown and set in the center. A knife inserted near the center should come out clean.
09 - Cool for 10 minutes before serving. Dust with powdered sugar if desired. Serve warm with maple syrup, lemon curd, or whipped cream.