Put the pretzel pieces into a resealable plastic bag and crush into very small bits (a meat tenderizer or a rolling pin works great for this).
In a small bowl, combine the peanut butter, butter, brown sugar and salt. Mix until all of the ingredients are completely blended and smooth. Add the pretzel bits to the peanut butter mixture and mix thoroughly. Then, add the powdered sugar and mix until completely combined.
Line a baking sheet with wax paper. Using a small cookie or ice cream scoop, (or about 2 teaspoons worth of peanut butter mixture), gently shape the mixture into a ball with your fingers. Place the ball on the wax paper-lined cookie sheet and repeat with the remaining peanut butter mixture. Place the baking sheet into the refrigerator and chill for at least 30 minutes.
When ready to dip the truffles, microwave the chocolate chips and vegetable shortening together in a small bowl in 30-second increments, stirring after each, until completely melted and smooth. This took me 3 - 30 sec increments.
Working one at a time, dip one peanut butter-pretzel ball into the melted chocolate and use a fork to roll it around, ensuring that it is completely coated with chocolate. Let any extra chocolate drip off and place back on the wax paper-lined sheet. Repeat with all of the peanut butter-pretzel balls. Sprinkle the chocolate covered truffles with the english toffee bits while the chocolate is still warm so the toffee bits stick.
Return the baking sheet to the refrigerator and chill for at least 30 minutes. Garnish with a drizzle of melted peanut butter (use a fork or a chop stick (if you have one) to drizzle the melted peanut butter) and enjoy. Store in an airtight container in the refrigerator.