Place a 12-cup or two 6-cup muffin tins in oven and preheat oven to 425° (with muffin tins in oven).
Meanwhile, combine pancake ingredients in a blender and mix well, until frothy. Leave in blender while you start the blueberry sauce.
In a small saucepan, combine the blueberry sauce ingredients. Place on stove-top over medium heat and bring to a boil, stirring regularly. Once boiling, reduce heat to low and simmer until sauce thickens, 3-5 minutes. Turn heat off and leave on stove.
When oven is pre-heated, melt 2 more Tbsp. butter. Remove hot tins from oven and quickly brush bottoms and sides of pan with melted butter. Turn blender on for a few seconds to re-mix batter, then quickly pour in to hot muffin cups, dividing equally between 12 cups, filling about 1/2-2/3 full.
Place in oven and bake for 15-18 minutes, or until puffy and deep golden colour. Remove from oven (pancakes will quickly deflate). Turn heat on under blueberry sauce to re-heat. Once warm, remove pancakes to serving plates and spoon warm blueberry sauce over. Garnish with icing sugar.
These mini dutch baby pancakes freeze well, as does the blueberry sauce. To re-heat, simply place frozen dutch babies on a baking sheet and loosely cover with a piece of aluminum foil. Place into pre-heated 350 oven until warmed through, 10-15 minutes. Sauce can be re-heated in microwave or a small saucepan.
Be sure to read the "Cook's Notes" in the original post, for more tips for this recipe!