In a small skillet over medium-low heat, combine oats, almond flour, brown sugar, butter, and salt. Cook for 3-4 minutes, stirring constantly, until golden and fragrant. The mixture should clump slightly and smell like toasted nuts. Transfer to a plate to cool completely.

In a high-speed blender, combine frozen blueberries, frozen banana, Greek yogurt, almond butter, vanilla, cinnamon, and 2 tablespoons of milk. Start on low, then increase to high, using the tamper to push ingredients down. Add remaining milk only if needed. You want a thick, soft-serve consistency that holds its shape - not pourable.

Immediately divide the smoothie base between two shallow bowls, using a spoon to create swoops and ridges. Sprinkle generously with the cooled streusel, then add fresh blueberries and sliced almonds. Serve right away with a spoon - this is meant to be eaten thick, not sipped.