Preheat oven to 450F (regular bake setting/not convection bake).
Mix the Dutch baby batter: Combine all the ingredients in a blender and blend to combine. Leave in blender and allow to stand 20-30 minutes.
When ready to cook, put empty skillet into the oven for 5 minutes. Re-blend batter briefly and have handy next to the oven. Also have your fully-cooked sausage and blueberries at the ready. Remove from oven (careful, it's hot!). Add the 1 Tbsp butter to the hot pan and allow to melt, then pour the batter into the pan. Arrange the sausage around the pan and scatter the blueberries over-top.
Place into 450F oven and bake, undisturbed, for 22-25 minutes, or until puffed and golden.
Remove from oven and let stand a minute or two. Dust with icing/confectioners' sugar and drizzle with maple syrup to serve.
Notes
1. Use either store-bought fully-cooked breakfast sausages OR pre-cook the sausages yourself. You can do this well ahead and refrigerate, if you like. You can also make use of the preheating oven to cook the sausages right before making the Dutch baby. Simply throw them in the skillet and into the preheating oven, cooking until they are cooked through and golden. Remove any excess fat from the pan and leave a bit and use it to replace the butter for the pan. You can pour the batter over-top of the sausages in the pan.Be sure to read the notes above the Recipe Card for substitution suggestions and tips for making this recipe. You will also find Step-by-Step photos for reference.