Preheat the oven to 350 degrees F. Line a muffin tray with 9 silicone muffin cups. Alternatively, you can grease a muffin tin with non-stick cooking spray or coconut oil. This is an important step as this will help you get the granola cups out much more easily. In a large bowl, combine the oats, mashed banana, peanut butter, maple syrup, vanilla, cinnamon and salt. Mix until combined (it helps if you use your hands). Allow mixture to sit for 5 minutes.
Split the granola mixture evenly between the 9 muffin holes.
Next, use your fingers or back of a spoon to shape the granola into little cups, forming a hollow center.
Bake the granola cups in the oven for 18-20 minutes.
Allow the cups to cool for at least 30 minutes before removing them from the muffin pan. Otherwise they might fall apart.
When they are ready to be removed from the muffin pan, carefully pop them out of the silicone cups or gently slide a paring knife along the edges of the cups, to loosen them from the muffin tin.
Fill them with yogurt and top with mixed berries. Serve and enjoy!