Cream the softened butter, brown sugar, and granulated sugar for 3 minutes.
227 g salted butter, 220 g brown sugar, 150 g granulated sugar
Add the egg, sourdough discard, and vanilla extract. Beat for another 3 minutes.
1 large egg, 75 g sourdough discard, 13 g vanilla extract
In a separate bowl, combine the flour, baking soda, and salt.
420 g all-purpose flour, 5 g baking soda, 5 g salt
Add the dry ingredients to the wet ingredients and mix by hand just until combined. The dough will be thick.
Gently fold in the chocolate morsels, chocolate chunks, and chopped English toffee.
270 g semisweet and dark chocolate morsels and chunks, 70 g English toffee candy bar
Cover the dough and refrigerate for 30 minutes up to 8 hours.
Preheat the oven to 350°F and line a baking sheet with parchment paper.
Scoop the dough onto the baking sheet, leaving space between the cookies.
Bake for approximately 9 minutes, watching carefully to avoid overbaking.
Allow the cookies to cool on the baking sheet for 2–3 minutes before transferring them to a cooling rack.
