In a large bowl, cream together butter and sugar for two minutes using a hand-held mixer. Add the eggs and vanilla and beat for another minute.

In a separate medium bowl, combine flour, baking soda, salt and corn starch. Add to the wet ingredients and mix until completely combined.

Fold in the pretzels and toffee pieces. Scrape dough from sides of bowl, cover bowl with plastic wrap, and chill dough for a minimum of 2 hours.

Pre-heat oven to 375°F. Roll dough into 1.5 tbsp balls. Press a Rolo into the dough and sculpt the dough around the rolo.

Bake on parchment or silicone baking mat-lined cookie sheets for 8-10 minutes, until tops are lightly golden and puffy.

Allow to cool 5 minutes on cookie sheet before transferring to a wire rack to cool completely.