Preheat oven to 350°F (177°C). Line two 12-count muffin pans with liners. Set aside.

Using a stand or handheld electric mixer on medium speed, beat together the cake mix, pudding mix, eggs, oil, milk and sour cream. Beat until well combined, about 2 minutes. Scoop the batter evenly into cupcake liners.

Bake for 20–25 minutes or until a toothpick inserted in the center comes out clean. Remove the cupcakes from the oven and cool completely in the pan.

(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 rubber 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 and garnish with a pretzel twist and salted caramel, if desired.

Cover and store leftover cupcakes at room temperature for up to 1 day or in the refrigerator for up to 5 days.