kosher salt, and lemon juice, and stir until the butter is melted. if you are struggling with hard caramel and un-melted butter, gently heat the pot again over medium heat, stirring until everything is even.
pour into a glass dish and let sit until ready to use.
in a small saucepan, melt the stick of butter over medium-low heat. add in the sugar after the butter has melted and continue to heat while stirring. heat for another 2 to 3 minutes until a nice, thick, smooth butter-sugar mixture has formed.
pour the butter-sugar mixture into a mixing bowl or a stand mixer, and add in the cocoa powder, salt, baking powder, and vanilla. 