Chocolate Oatmeal Cookies with Toffee Recipe

0 Preheat the oven to 350°F / 177°C.
1 Lightly grease a sheet pan or line it with a Silpat baking mat or parchment paper.
2 In a small bowl, whisk together the flour, baking soda, and salt. Set aside.
3 In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, white sugar, and brown sugar on medium-high until light and creamy, about 3 minutes (it should resemble fluffy frosting).
4 Add the egg and vanilla and mix on low until evenly combined, scraping down the bowl as needed.
5 Add the flour mixture all at once and mix on low until just combined (stop mixing as soon as there are no dry spots of flour in the dough - do not overmix). 
6 Add oats, dark chocolate, and toffee chips, and mix into the batter on low just until combined. 
7 Use a heaping tablespoon to scoop out even portions of cookie dough and arrange on the prepared baking sheet.
8 Bake the cookies until the edges are just starting to turn golden brown and the centers are still pale and soft (they will continue to firm up and darken after you remove them from the oven), 12 to 14 minutes. 
9 When you remove the sheet pan from the oven, tap it firmly on the kitchen counter a few times to deflate the cookies.
10 Sprinkle the tops of the cookies with flaked sea salt. 
11 Leave the cookies on the sheet pan to cool for 10 minutes before transferring them to a cooling rack. 
12 Store cookies in a sealed container at room temperature for up to 3 days.