Add the butter and mix until mixture resembles coarse crumbs.
Add half of the wet ingredients into the bowl with the flour and beat on medium speed for one minute.
Scrape the bowl, add the other half of the wet ingredients and continue beating on medium high for another 30 seconds.
Transfer the cupcakes on a rack and let them cool completely.
Return to heat, stir until well incorporated and let it boil until it reaches 226°F (108°C). Remove from heat and transfer to a heatproof bowl to cool. Add the salt and stir gently.
When the cupcakes have cooled, cut a hole in the center and fill them with some caramel.
When the caramel is lukewarm but still a little runny, pour some over the frosted cupcakes.
Before starting, bring all of the ingredients at room temperature.
The butter should be SOFT, otherwise it will not get beaten well, affecting the final texture of the cupcakes.
Make sure the cupcakes have cooled completely before frosting them!
If you don’t have a thermometer you can let the caramel boil for two minutes after you add the cream and test the consistency by dropping a small dollop in a glass with cold water. The caramel should reach the soft ball stage. This method is not as accurate as a thermometer, so results may vary.
If caramel is a bit warm when pouring it over the cupcakes, it may melt the ganache slightly. If you refrigerate the cupcakes for 10 minutes before pouring the caramel, it will help the ganache to hold its shape.
The cupcakes, because of the ganache, will keep at room temperature for up to 2 days or refrigerated for up to 5 days.