For Cupcakes

1. Adjust the oven rack to the center of the oven and pre-heat oven to 350˚ F. Place 12 cupcake liners in a muffin tin pan.
2. Whisk together the dry ingredients: flour, baking powder, baking soda and salt in a medium bowl. Set aside.
3. Beat the butter and sugar in a large bowl with a hand mixer. Beat on medium for about 5 minutes, until light and fluffy.
4. Add one egg at a time and mix until combined. Add vanilla.
5. Alternate mixing in the dry ingredients in 3 portions and the buttermilk in two portions to the wet ingredients until everything is added. Mix until just combined.
6. Mix in sprinkles with a few turns of a sturdy spoon.
7. Fill each liner three-fourths full of batter.
8. Place the pan in the oven for 20 to 22 minutes. Cupcakes are done when starting to color at the edges and a toothpick comes out clean. Let cool in the pan for 10 minutes before removing. Let cool completely before piping on frosting.

For Ermine Buttercream

1. Add flour and milk to a saucepan over medium heat. Whisk the mixture until it is like pudding in texture (2-3 minutes). Take it off heat and whisk in the vanilla and salt. Transfer it to a heat proof bowl and allow to cool to room temperature. Cover the surface with plastic wrap so a film does not form.
2. Add the butter and sugar to the bowl of standing mixer with a paddle attachment. Mix on medium for 5-6 minutes until light and fluffy. Scrape down the sides, when needed.
3. Once the flour mixture is cooled, add it to the butter/sugar one scoop at a time while the mixer is on medium. Continue to mix until smooth.
4. Remove bowl from mixer and transfer the frosting to a piping bag with a piping tip, like a 1M. Pipe the frosting in a swirl (about 2 inches high) on top of each cupcake. Top with sprinkles if desired.

For Swiss Meringue Buttercream

1. Start by cleaning the bowl of a stand mixer and the whisk attachment with lemon juice or vinegar. It’s important that the bowl and whisk are free from grease and residue when making the meringue.
2. Add the egg whites and sugar to the bowl and set it over a medium saucepan filled with 2 inches of water. Make sure that the mixing bowl does not touch the water below. Simmer over low heat, whisking the eggs and sugar together until the sugar granules are dissolved. This will take 5 to 10 minutes. Use your fingers to test the texture of the mixture – it should feel smooth, not grainy. If using a digital or candy thermometer, heat the mixture to about 150°F.
3. Remove the bowl from the heat and place it on the stand mixer. Beat the egg whites and sugar on high speed until stiff peaks form. This will take between 8 and 10 minutes. Feel the bottom of the bowl with your hands – it should no longer feel warm.
4. Reduce the speed to medium and add the butter, one tablespoon at time, mixing well between each addition. Once all of the butter has been added, beat the mixture on medium-high for 2 to 3 minutes until light and fluffy.
5. If the buttercream looks curdled or runny, continue mixing on high speed until it comes back together. If it doesn’t emulsify within 6 to 10 minutes of mixing, place the bowl in the refrigerator for 20 minutes and try mixing again once chilled.
6. Scrap down the sides of the bowl, add the salt and mix for 20 to 30 seconds to incorporate. Fill a piping bag with the buttercream and pipe swirls on top of the cooled cupcakes.