In a medium bowl, whisk together the flour, granulated sugar, baking powder, baking soda, and salt.
In a separate bowl, whisk together the buttermilk, egg, melted butter, and vanilla extract until combined.
Pour the wet ingredients into the dry ingredients and stir until just combined; do not overmix.
In a small bowl, combine the softened cream cheese and powdered sugar until smooth.
Gently fold the chopped strawberries and blueberries into the cream cheese mixture.
Preheat a non-stick skillet or griddle over medium heat and lightly coat with cooking spray.
Using a tablespoon, pour small rounds of pancake batter onto the skillet (about 1 1/2 inches in diameter).
Cook for 1-2 minutes until bubbles form on the surface and edges look set.
Place about 1 teaspoon of the cream cheese and fruit filling on top of each pancake round.
Top each filled pancake with another tablespoon of batter to cover the filling.
Cook for an additional 1-2 minutes until the bottom pancake is golden brown and the top batter is cooked through.
Carefully flip the pancake poppers and cook for 1 more minute until golden brown on all sides.
Remove the pancake poppers from the skillet and let cool slightly before serving.