Line a large baking sheet with aluminum foil and fit in a wire rack. Spread bacon in 1 even layer on the greased wire rack and cook it in the oven at 400℉ for about 20-25 minutes, depending on thickness.
Save the bacon grease!
Cupcakes:
Preheat the oven to 350℉ and line a muffin pan with cupcake liners. (I recommend parchment paper liners but you can use any your prefer.)
Sift flour, baking soda, salt, and baking powder together and set aside.
Combine vegetable oil, bacon grease, vanilla extract, and maple syrup. (And maple extract if using.)
Make sure your other ingredients are ready.
In a bowl of an electric mixer (use paddle attachment), beat egg whites for about 30 seconds and slowly start pouring in sugar. Beat for 2-3 minutes, until white and fluffy.
Start pouring in oil mixture, slowly, as the eggs are still beating on medium-high.
Lower the speed to low.
Alternating, add flour mixture and buttermilk in two parts. Mix until just combined. Scrape sides and bottom of the bowl and low mix a couple more seconds until incorporated.
Divide batter among the cupcake cups, filling them about ⅔ of the day. (I recommend using an ice cream scoop so all the cupcakes are even.) Tap the cupcake pan on the counter a couple of times to help air bubbles come up.
Bake for 18-20 minutes. Take out of the oven and let them rest for 5-10 minutes. Gently take the cupcakes out onto the wire rack to cool.
Drizzle about a teaspoon of maple syrup on to of each cupcake while they are still warm.
Cool completely before frosting!
Frosting:
Beat softened butter in the electric mixer, on medium-high speed, for about 2 minutes.
Lower speed to low and carefully mix in powder sugar, salt and maple syrup. Once sugar is incorporated, scrape sides and bottom of the bowl and raise speed to medium. Beat for another 2-3 minutes.
Transfer frosting into a piping bag with desired tip attached (I used 1M). Pipe cooled cupcakes.
Crumble crispy bacon and divide it on top of piped cupcakes.
Drizzle each cupcake with some maple syrup.
Notes
Measure properly! Make sure you spoon the flour into the measuring cup instead of dunking the cup directly into the bag! Then, cut the excess at the top with the back of a knife to level. If you dunk the cup, you’ll pack the flour into the cup and that could result in dense cupcakes.
Use room temperature ingredients for cupcakes and frosting. Pull eggs, buttermilk, and butter about 30-45 minutes before baking. Make sure to measure out the buttermilk first and then let it warm up.
Storing: It’s always best to store frosted cupcakes in the refrigerator! Store them in an air-tight container like a large food storage container with a lid or in the muffin pan if it came with a lid. Frosted cupcakes should be good for 3-4 days in the refrigerator. You can let them warm up on the counter before serving.
Can cook bacon ahead: you can easily cook bacon ahead of time, just make sure to save the bacon grease! Store bacon grease and bacon separately, in air-tight containers, in the refrigerator. Reheat the grease and bacon before using.