The toffee notes in the dough--rich brown butter and dark brown sugar--are carried through in the mix-ins with a combination of toffee chips and dark chocolate chips.
4 oz butter
2.5 oz brown sugar
2.5 oz sugar
1 tsp espresso powder
1 tsp vanilla
1/2 tsp salt
1 egg
5 oz flour
1/4 tsp baking powder
1/4 tsp baking soda
6 oz toffee chips & chocolate chips
The first step is to brown the butter. This only takes a few minutes on the stove. Make it up to a couple of weeks in advance so it'll be ready for you on baking day.
Cream brown butter, sugars, salt, and vanilla together. Add the espresso powder for deeper flavor. In this batch, I also added a tiny bit of cocoa powder, but you don't have to.
Once you've creamed the butter, sugar, and flavorings, blend in the egg. Then whisk together the flour, baking soda and powder, and mix that in on low speed.
Then mix in both the dark chocolate chips and the toffee chips. TIP: You can also use chopped Heath bars and/or your favorite dark chocolate bar all chopped up.
Once the dough is finished, cover it and let it ripen in the fridge for at least an hour and up to two days. This allows the flour to fully hydrate and the flavors to develop and mingle together.