Preheat oven to 350 degrees. Line cupcake tins with 17 cupcake grease-proof liners.
Using a sifter or fine mesh strainer, sift the Dry Ingredients into a large bowl, then whisk until well blended.
Whisk the egg whites in a separate medium to large sized bowl until foamy. Add the remaining Wet Ingredients and whisk until smooth and well-blended.
Melt saltedbutter in the microwave (or over the stove) until just melted. Avoid overcooking.
Pour Wet Ingredients over the Dry Ingredients, then immediately before stirring add in the apple cider vinegar. Whisk everything together--the apple cider vinegar will bubble slightly as it reacts with the wet and dry ingredients. Pour the melted Butter into the batter and whisk until smooth, uniform and lump-free.
Stir in the 50 grams Halloween Jimmy Sprinkles, and immediately begin scooping the cupcakes (before the sprinkles melt)
Use a 2-oz scoop (¼ cup) to divide your batter into 17 standard-sized cupcakes with greaseproof cupcake liners. Sprinkle a few additional Halloween sprinkles on top of the batter. Start by baking at 350 degrees for 10 minutes, then turn the oven down to 300 degrees for an additional 4-8 minutes or until they pass the toothpick test.
While the cupcakes cools, make a simple syrup by combining 2 teaspoons water and 2 teaspoons sugar in a small microwave-safe bowl. Microwave until the sugar is dissolved after whisking, about 20-30 seconds.
Use a silicone pastry brush to lightly brush the cooled cupcakes with simple syrup.
Make Frosting
Prepare the creamy vanilla bakery buttercream frosting recipe according to its instructions, and dye with gel food coloring, if desired. Frost the cooled cupcakes and decorate with Halloween sprinkles and candy eyes. Enjoy!
Notes
Read my article Instant Clearjel: a Magical Little-Known Bakery Ingredient to see why I think this ingredient is worth having in your pantry. Instant Clearjel must always be whisked thoroughly with other dry ingredients before being added to wet ingredients to avoid clumping. (Make sure what you use is labeled as “Instant.” Cooktype Clearjel is a different product that does not work the same in cakes). If you need a substitute, in the cake batter you may substitute 4 tablespoon Vanilla Instant Pudding Mix in place of the 2 tablespoon Instant Clearjel in a 1x batch. This will make the cupcakes a darker color.