Combine in a large mixing bowl peanut butter, butter, brown sugar, milk and vanilla and blend until smooth.
Add egg and mix well.
Combine in a small bowl flour, salt and baking soda. Gradually add to peanut butter mixture and cream until blended. For easier handling, wrap dough in plastic wrap and place in refrigerator until chilled, at least 1 hour.
Preheat oven to 375F and coat a cookie sheet with cooking spray. Using a cookie dough scoop or tablespoon, scoop dough into balls and roll. Coat with granulated sugar and place on cookie sheet about 2 inches apart. Dip a fork in water and crisscross the cookie to flatten.
Bake at 375F for 7-9 minutes or until lightly golden brown. Cool completely.
Combine in a medium bowl frosting and strawberry jam. Depending on the flavor, you may want to add strawberry extract, and to add a little color, mix in food coloring. Gently stir in COOL WHIP.
Fill a decorator bag with the strawberry filling or spread with an offset spatula onto bottom side of 1 cookie. Top with another cookie and press together lightly. Repeat with remaining cookies.