Add ¾ cup sugar and the water to a small saucepan on medium heat.
While the sugar syrup is cooking, add the egg whites to the bowl of a stand mixer fitted with the whisk attachment and beat on high speed. When the egg whites start foaming, slowly add the remaining sugar and continue beating until stiff peaks form. If your syrup is not ready, lower the speed, but do not turn the mixer off.
The syrup is ready when it pours off the spoon in a steady stream or reaches 235F.
With the stand mixer on high speed, slowly pour the syrup into the egg whites, but DO NOT let the syrup hit the whisk. It should be a steady stream into the bowl.
Continue beating the frosting until the bowl cools down and feels barely warm. Switch to the paddle attachment and add the butter one tablespoon at a time.
Continue beating until frosting stiffens (this can take 5-10 minutes). If it’s not stiffening then put it in the fridge for 20 minutes, and then try again.
Add the vanilla, salt, and maple syrup and mix until combined.
Pipe or spread frosting on the cupcakes and then top with bacon.