Make the streusel: In a medium bowl, whisk together the flour, oats, brown sugar, cinnamon, and salt.
Add the cold butter and use your fingers to rub it into the dry ingredients until the mixture resembles coarse crumbs.
Spread the mixture in an even layer on the prepared baking sheet and bake for 15 minutes. Once the streusel is done baking, remove from oven and set aside to cool slightly.
While the streusel is baking, prepare the oats: Add the rolled oats and milk to a pot and bring the heat to medium.
When the mixture is at a low boil, cover and reduce heat to low heat for 5 minutes.
Stir in the wild blueberries, maple syrup, cinnamon, cardamom, and cloves. Heat for 5 minutes.
Transfer the oats to a bowl and top with strawberries, raspberries, and streusel.