Preheat oven to 375(F) Lightly grease several baking sheets with butter or cooking spray.
In the bowl of an electric mixer with a paddle attachment or using a handheld mixer, beat the butter at medium speed until creamy and smooth, about 1 to 2 minutes. Add the sugar and beat the mixture until light and fluffy, about 5 minutes. Be sure to scrape down the sides of the bowl occasionally to incorporate all the sugar into the butter. Beat in the eggs, one at a time, beating well after each egg to thoroughly combine. Beat in the vanilla.
In a separate medium bowl, whisk together the flour, baking powder, baking soda, and salt. Add the flour mixture to the butter mixture, beating just until combined. Using a wooden spoon or rubber spatuala, fold in the chocolate chips, toffee chips and pecans (if using).
Drop the batter by rounded tablespoonfuls onto the prepared baking sheets. (A mini ice-cream scoop works great for this.)
Bake one sheet at a time for about 9 to 10 minutes until set and the edges are light golden brown.
Let cool on wire racks.