Heat a heavy skillet or grill over medium-low heat.
In a medium bowl, mix the flour, sugar, baking powder and salt. Set aside.
In a separate bowl, mix the evaporated milk, lemon zest and juice. Allow to sit for 5 minutes, then add the egg and vanilla. Mix to combine.
Pour the wet mixture into the dry ingredients. Stir gently to combine. Stir in the melted butter. Splash in more evaporated milk if the mixture is overly thick. Stir in the blueberries.
Melt a little of the softened butter in the heated skillet.
Drop the batter by 1/4 or 1/3 cup measures and fry the pancakes on both sides for a couple of minutes until golden.