Preheat oven to 350°F (177°C). Line 12-count muffin pan with paper liners, plus a second pan with only 2 liners. Fill empty cups halfway with water to prevent the pan from warping. Set aside.

In a large bowl, whisk together the flour, baking powder, and salt. In a separate medium bowl, beat the butter and sugars together at medium-high speed until light and fluffy, 2–3 minutes. Add the eggs and vanilla. Beat until combined. Slowly mix in the dry ingredients until no flour remains, scraping down the sides of the bowl as needed. Slowly stir in the milk. Do not over-mix the batter.

Fill each cupcake liner only 1/2 way full with batter. Bake cupcakes for 22–23 minutes, or until a toothpick inserted in the center of the cupcake comes out clean. Let the cupcakes cool before frosting, about 1 hour.

(This frosting is popular, so we have a separate salted caramel frosting post if you need more help making it.) Combine the butter and brown sugar in a saucepan over medium heat. With a silicone spatula or wooden spoon, stir constantly as the butter melts. Once butter has melted, switch to a whisk to make sure the two are really combined. (Otherwise, you might see an oily layer around the edges where they’re still a bit separated; you do not want that.) Once melted butter and brown sugar are combined, add 3 Tablespoons of heavy cream and the salt. Whisk to combine, then stop whisking and attach a candy thermometer to your pan, making sure the bulb is not touching the bottom of the pan. Let the caramel boil, giving it a quick whisk every 30 seconds or so, until the temperature reaches 230°F (110°C). On my stove, it takes just under 2 minutes.

Remove the saucepan from heat, give it another quick whisk, and let cool for a minute. Carefully transfer the salted caramel to a heat-proof mixing bowl set on a cooling rack and cool for just 15–20 minutes before continuing. The caramel sauce thickens during this time.

Sift in confectioners’ sugar and add remaining 2 Tablespoons of heavy cream. With a handheld or stand mixer fitted with a whisk attachment, beat on medium-low speed until the ingredients are incorporated. Turn mixer up to high speed and beat for 1 minute. Avoid over-mixing or the frosting will begin to “break” and separate. Let it sit for at least 20–30 minutes before filling your piping bag, to give it a chance to thicken up to a pipeable consistency.

Frost cooled cupcakes. Cover and store leftover cupcakes at room temperature for up to 1 day or in the refrigerator for up to 5 days. I recommend a cupcake carrier for storing and transporting decorated cupcakes.