Preheat the oven to 350°. Line a muffin pan with paper liners and spray each with vegetable spray. Set aside.
In a small bowl, combine the flour, sugar, baking powder, cardamom and salt and whisk to combine.
In a medium bowl whisk together the egg, milk, vanilla and melted butter. Stir in the flour mixture just until moistened. Stir in the blueberries and set aside.
Make the streusel
Add the flour, sugar and cold butter to the bowl of a food processor and pulse several times until a fine meal has formed that will clump together when you press it between your fingertips. Transfer the streusel to a small bowl and add the sliced almonds. Toss with your fingers to combine.
Spoon the batter into the prepared muffin cups. Top the muffins with sliced strawberries and mound the streusel on top of the berries.
Bake for 18-22, until a cake tester comes out clean and top is golden. Cool for 10 minutes in the muffin tin, then transfer to a serving platter.
Notes
These muffins are loaded with berries, so you may need a fork and plate to eat them.