1. Heat oven to 375 degrees F.Cookies:
2. Using freestanding electric mixer fitted with a paddle attachment, beat butter on medium speed until smooth and creamy, about 2 minutes. Add sugar; beat until smooth and creamy, about 2 minutes. Beat in vanilla. On low speed, gradually beat in the flour and salt. Beat in milk and chopped chocolate until blended.
3. Spread the chopped peanuts on a plate. Roll dough into 1-1/2-inch balls; dip top of each ball in chopped peanuts. Place balls, about 1-1/2 inches apart, on ungreased baking sheets. Push your thumb into the middle of each ball to make depression.
4. Bake in 375 degrees F oven 10 to 12 minutes or until light golden brown. Transfer cookies to wire rack; let cool.Filling:
5. Place chocolate chips in top of double boiler or bowl. Place over hot water (dont let bottom of bowl touch water); melt chocolate. Stir in the peanut butter, corn syrup, water and vanilla. Remove the bowl from over the hot water; let the chocolate mixture cool for 5 minutes.
6. Spoon about 1 teaspoon of the filling into the center depression of each cookie. Store the cookies in airtight container at room temperature for up to 3 days.