Preparing your oven - Preheat your oven to 170C / 340F (fan off), 150C / 300F (fan on). I like baking with the fan on for an even rise. Position your rack in the middle of the oven. Line your cupcake tin with cupcake liners.
Combine dry ingredients - In a medium sized bowl, whisk together the flour, baking powder and salt. Set aside.
Beat the eggs and sugar - Add the eggs to a large mixing bowl (glass or metal), and use an electric hand mixer to beat until frothy, about 1 minute. A stand mixer with a whisk attachment also works. With the mixer on medium-high speed, add the sugar a spoonful at a time. It’ll take about a minute. Once all the sugar is added, keep beating on medium-high speed for 6 minutes until the mixture is pale, thickened, and tripled in size.
Add dry ingredients to egg mixture - Add half the dry ingredients to the egg mixture and mix on low speed until just combined. Repeat with the rest. The batter will be thick. Avoid overmixing the batter, small lumps are fine, they’ll disappear in the next step.
Heat milk and butter - Heat the milk and butter in a saucepan over medium heat, stirring continuously, until it reaches about 60C/140F or small bubbles form around the edges. Do not let it boil. Alternatively, you can also do this in a heatproof jug in the microwave. Mine takes about 90 seconds for the butter to melt.
Add hot milk - Add half the hot milk mixture, along with the oil and both vanillas. Mix on low speed until combined. Add the rest of the milk mixture and mix again until smooth. The batter will be thin and pour in a steady ribbon.
Divide the batter - Divide the batter evenly between the cupcake liners filling them about 3/4 of the way. Tap the cupcake tin on the counter a couple times to release any air bubbles in the batter for a nice flat even rise.
Bake - Bake on the middle rack for 17-18 minutes, or until a toothpick inserted in the center comes out clean. The cupcakes will be lightly golden around the edges and spring back when gently touched. If they sink and don’t spring back, bake for a couple more minutes.
Cooling the cupcakes - As soon as they come out of the oven, transfer them to a cooling rack, and let them cool completely at room temperature.