- Beat the butter, sugar, brown sugar and orange zest together until smooth. Add the egg and beat until combined.
- Sift in the flour and baking soda and stir until blended, then stir in the toffee bits.
- Shape the dough into two logs about 9 inches long and 2 inches across and wrap in plastic wrap. Once wrapped, gently flatten the dough on 4 sides, to create a square shape. Chill the dough for at least 2 hours before baking.
- Preheat the oven to 350°F and line 3 baking trays with parchment paper.
- Slice the logs into cookies that are ¼ inch wide and place them onto the prepared trays, leaving 2 inches between each cookie (these do spread as they bake). Sprinkle the top of each cookie with a little bit of sea salt.
- Bake the cookies for about 13 minutes, until they have browned just lightly on the bottom.
- Cool the cookies on the tray and then store in an airtight container.
The cookies will keep for up to a week.
From Back to Baking, Whitecap Books, 2011