These sweet little thumbprint cookies will disappear quickly, you may want to make a double batch.
Separate egg; place yolk and white in separate bowls. Cover and chill egg white until needed. In a large mixing bowl beat butter with an electric mixer for 30 seconds.
Add sugar and beat well. Beat in egg yolk, milk, and vanilla.
In another bowl stir together the flour, cocoa powder, and salt.
Add flour mixture to butter mixture and beat until well combined.
Wrap the cookie dough in plastic wrap and chill for 2 hours or until easy to handle.
Preheat oven to 350 degrees F.
Lightly grease a cookie sheet.
In a small microwave proof bowl heat and stir the caramel chips or caramels and whipping cream. Microwave for 30 second intervals. Set aside. Or put the caramel chips or caramels into a small saucepan and slowly heat on the stovetop until melted and stir in the whipping cream very well.
Slightly beat reserved egg white. Shape the dough into 1-inch balls.
Roll the balls in egg white, then roll in the chopped nuts to coat.
Place balls 1 inch apart on prepared cookie sheet. Using your thumb, make an indentation in the center of each cookie.
Bake for 8-10 minutes or until edges are firm. If cookie centers puff during baking, repress with your thumb or the back of a spoon if they are too hot.
Spoon the melted caramel mixture into indentations of cookies. Transfer cookies to wire racks; cool. (If necessary, reheat caramel mixture to keep it spoonable.)
In another microwavable bowl heat and stir chocolate pieces until chocolate is melted and mixture is smooth, or do on the stovetop in a small saucepan
Add in oil until chocolate mixture drizzles off the spoon. Let cool slightly.
Drizzle chocolate mixture over tops of cookies.* Let stand until chocolate is set.
Makes 36 cookies