Using a stand or hand mixer cream together the softened butter, brown sugar and vanilla until fluffy.
Add the all-purpose flour 1/4 cup at a time mixing just until combined.
Mix-in the mini chocolate chips by hand.
Line a cookie sheet with wax paper. Roll the cookie dough into 1-inch balls and place on the cookie sheet. Place into the freezer for 30 minutes or until firm.
To make the coating,
in a microwave safe bowl melt together the milk chocolate chips, semi-sweet chocolate chips and vegetable shortening. Melt in 20 second increments stopping to stir each time. Repeat until completely smooth.
Dip the truffles into the chocolate using 2 forks letting the excess drip off. Place back onto the wax paper lined cookie sheet. Drizzle the tops with the remaining chocolate. Chill until set.