2 hrs 10 min
1 cup Land O Lakes® Butter, softened
3 1/2 cups powdered sugar
1/3 cup prepared caramel sauce
1 teaspoon sea salt
1 teaspoon vanilla
Combine cake mix, 1/2 cup melted butter, water and eggs in large bowl; beat at medium speed until smooth. Let batter rest for 30 minutes.
Heat oven to 400°F. Drop batter by slightly rounded teaspoonfuls, 2 inches apart, onto parchment-lined or lightly greased cookie sheets.
Sprinkle each cookie with sea salt. Bake for 5 to 7 minutes or until toothpick inserted in center comes out clean. Transfer to wire cooling rack.
Place 1 cup butter in medium bowl. Beat at medium speed until creamy. Reduce speed to low; gradually add powdered sugar. Beat until well mixed. Add caramel sauce, 1 teaspoon sea salt and vanilla. Beat until well mixed.
Pipe or spread rounded teaspoonful filling onto bottom of 1 cookie; place second cookie, bottom-side down over filling. Repeat with remaining cookies and filling.