CakePreheat oven to 350 degrees F and line muffin pans with liners or spray with non-stick.
In a large bowl, with a stand mixer or whisk, beat butter, applesauce and sugar until smooth. Add in eggs and stir until well-combined. Stir in lemon juice, extract*, and buttermilk.
Add flour, baking powder, salt and food colouring and stir just until combined.
Spoon batter into lined or sprayed muffin tins about ¾ full. I baked mine exactly 15 minutes at 350 degrees F. Bake until toothpick comes out clean or with moist crumbs. Coo while you prepare the frosting.
FrostingIn a small bowl, combine chocolate and milk and microwave at 50% power for 1 minute. Stir until smooth, putting back in the microwave for another 30 seconds if needed. Set aside to cool.
In a stand mixer beat butter until light and fluffy. Add cooled chocolate, icing sugar and vanilla. Beat slowly at first, increasing speed as the icing sugar is incorporated.
Beat on medium-high for 4-5 minutes until light and fluffy. Frost cooled cupcakes.
Notes
*The original recipe calls for lemon zest. If I had had lemon zest, I certainly would have added it instead of extract. But good, fresh lemons can be somewhat difficult to find here on a regular basis, and so I settled for extract.