Preheat the oven to 200°C / 392°F
Line the tray Line a 12 cup muffin tray with muffin paper cups.
Whisk dry ingredients Whisk flour, salt, sugar and baking powder.
Fold the wet ingredients: In a separate bowl mix the eggs, vanilla, melted butter, milk and sour cream. Fold them together.
Combine: Add the wet ingredients to the dry and fold them in together. No need to over mix and you'll probably see random specks of flour that's fine.
Fold in the blueberries and chocolate chips Use an ice-cream scoop or a regular spoon to fill each muffin paper cup with enough batter. Each cup will be pretty full.
Sprinkle some sugar over the muffin tops and bake.
Bake: Get the muffins into the oven and bake for 5 minutes on 200°C / 392°F and then without opening the oven turn it down to 180C / 356 F for 15 minutes or do the toothpick test " insert a toothpick into the muffin, it it comes out clean they're done". See notes below.
Cooling: Transfer the baked muffins onto a cooling rack as soon as they come out of the oven.