For Bundt Cake:
Preheat oven to 350 degrees . In a bowl, whisk the flour, baking powder and salt.
In an electric mixer fitted with the whisk attachment, beat the butter on high until creamy, 2 minutes. With the machine on, gradually add the sugar and beat, scraping the bowl, until fluffy, 8 minutes. Beat in the eggs one at a time, scraping the bowl. Beat in the vanilla. At low speed, add the flour mixture in three additions, alternating with the milk. At medium speed, mix until smooth. Transfer to prepared bundt pan; bake for 1 hour; invert and let cool on a rack. Transfer to a platter or cake stand.
For Lemon Frosting:
In an electric mixer, beat the butter and salt at medium speed until creamy about 1 minute.
Sift in the confectioners' sugar, 1 cup at a time, mixing at low speed to incorporate (the mixture will be crumbly). Beat at medium speed for 1 minute, then increase to high speed and beat until smooth, 3 to 4 minutes. Gradually add the lemon curd then beat until fluffy, 2 to 3 minutes. Beat grated lemon zest into the finished frosting.
Top cake with Lemon Frosting. Sprinkle with chopped store-bought candied lemon peel.