Preheat oven to 350 degrees.
Butter and flour individual mini bundt cake pans. Set aside.
Combine butter and sugar in a mixing bowl.
Beat the butter and sugar until smooth and light-colored. (about 5 minutes)
Sift flour, baking soda, and salt together in a second bowl. Set aside.
In a smaller bowl, combine buttermilk with 4 TBSP of lemon juice and lemon zest. Stir well.
Set aside the remaining 1 TBSP of fresh lemon juice.
Add eggs, one at a time, to the butter-sugar mixture. Beat after each egg is added.
Add dry ingredients alternately with wet ingredients, beating just until combined.
Pour batter equally into each of prepared mini pans.
Bake at 350 degrees for 35-40 minutes or until an inserted toothpick comes out clean.
Remove the pan from the oven.
Place pan on a wire rack until cool.
Run a knife around the edges of each of the cakes.
Flip cake pan over onto wire rack to completely cool.
Whisk together the 1 TBSP of lemon juice with 1 TBSP of water and 3/4 C confectioners' sugar.
If needed slowly add a tablespoon or more of water or confectioners' sugar.
Slowly pour icing over cake.
Spoon lemon curd in the center of each of the individual bundt cakes.
Top with whip cream, lemon wedge, and mint sprig