Step 1

Mix butter, shortening and brown sugar in a stand mixer using the paddle attachment until well combined.

Step 2

Add eggs, one at a time, mixing well after each addition. Mix in vanilla.

Step 3

Combine flour, baking soda, cream of tartar and salt in a separate bowl. Gradually add to the brown sugar mixture and mix well.

Step 4

Stir in toffee bits and pecans.

Step 5

Shape into two 10-inch rolls then wrap each in plastic. Freeze for 4 hours or until firm.

Step 6

Preheat oven to 375 degrees.

Step 7

Unwrap dough then cut into 1/2-inch slices. Place frozen cookie dough portions 2 inches apart on greased baking sheets.

Step 8

Bake at 375 degrees 9-11 minutes or until lightly browned. Cool until set before moving from the pans.