Step 1: Separate the egg whites from the yolks. Place the whites in one mixing bowl and the yolks in another.
Step 2: In the bowl with the egg yolks, add the full-fat sour cream, whole milk, dark brown sugar, salt, and vanilla extract. Whisk until smooth and well combined.
Step 3: In a separate bowl, whisk together the flour and baking powder.
Step 4: Gradually add the dry mixture to the wet mixture, stirring gently until just combined. Be careful not to overmix; a few lumps are okay.
Step 5: In the bowl with the egg whites, use a clean whisk to beat them until stiff peaks form. This step is crucial for making your pancakes light and airy.
Step 6: Gently fold the whipped egg whites into the pancake batter. This will add volume and fluffiness.
Step 7: Fold in the fresh blueberries, being careful not to crush them.
Step 8: Heat a non-stick skillet or griddle over medium heat and add a tablespoon of butter. Once it’s melted and bubbling, you're ready to cook!
Step 9: Pour about 1/4 cup of batter onto the skillet for each pancake. Cook until bubbles form on the surface and the edges look set, about 2-3 minutes. Flip and cook for another 2 minutes until golden brown.
Step 10: Stack your pancakes high on a plate and serve warm with a drizzle of maple syrup. Enjoy the fruits of your labor with family and friends!