Preheat the oven to 350° F, line cooled cookie sheets with parchment paper
Whisk together the flour, baking soda, salt and cornstarch in a separate bowl
In a large mixing bowl, cream butter, granulated and brown sugars until light and fluffy.
Add in egg and vanilla, mix until smooth.
Slowly incorporate your flour mixture with the wet ingredients.
Add in oats, chocolate chips and toffee bits. Start at a low speed and move to a higher speed until everything is well distributed.
Scoop dough out by the tablespoonful and place on prepared cookie sheets, leaving room for cookies to expand.
Bake for around 10 minutes, or until the edges of the cookies are golden but the middle still looks soft.
Allow cookies to cool on cookie sheets, then transfer to wire rack to finish cooling.
