
Preheat the oven to 375 degrees F (see note!). Line two large rimmed baking sheets with parchment paper. Lightly grease with cooking spray and set aside.
In a large bowl with a handheld electric mixer or in the bowl of a stand mixer fitted with the paddle attachment, combine the butter, granulated sugar, brown sugar, baking soda and salt. Mix until well combined, 1-2 minutes, scraping down the sides of the bowl as needed.
Add the vanilla and eggs and mix until the batter is light and fluffy, 1-2 minutes, scraping down the sides of the bowl as needed.
Add the flour and toffee bits and mix until no dry streaks remain.
Scoop the cookie dough into heaping tablespoons (I use my #40 cookie scoop) and roll into balls. Place about 2 inches apart on the prepared baking sheets and bake for 10-11 minutes until edges are set and very slightly golden - the middles will still be soft for a chewy cookie (bake longer for a crispier cookie).
Let the cookies rest for a minute or two on the baking sheets before removing to a wire rack to cool completely.