cookie secrets

This is a story about an accidental invention, a recipe born of cake-baking frustration and a quest for greatness, with beginnings in tragedy and a triumphant conclusion. This story clearly does not include quality photography, as evidenced above - my apologies.
Over the weekend, in honor of an ice-cream loving friend's birthday, I set out to create a recipe for a cake that would rival Ben and Jerry's Coffee Heathbar Crunch ice cream (swooooooon). Sadly, my lack of cake-related knowledge made it abundantly clear that such a task was sure to end in heartache (and a crappy cake), so instead, I altered my go-to cookie recipe, adding a few key flavors. It worked out well. Well enough that the remaining cookies were gone before I realized my only photo was sub-par. OH WELL.
Try this recipe plain, or make some scary-good sandwiches with coffee ice cream spread between.

Espresso Toffee Crunch Cookies
(adapted from Ambitious Kitchen's brown butter cookies, which are life changing)
you'll need...
2 1/4 cups all-purpose flour
2 T instant espresso powder (you can add slightly more at the end for a heavier coffee flavor)
1 1/2 tsp baking soda
1/4 tsp salt (this is adjusted, as I always have salted butter on hand. If you use unsalted, up to 1/2 tsp)
2 sticks butter, browned and cooled (see instructions below)
1 1/2 cups brown sugar
1/4 cup white sugar
1 egg plus 1 yolk
1 T greek yogurt
2 tsp vanilla extract
1 cup milk chocolate chips
1/2 cup dark chocolate chips
3/4 cup toffee pieces (you want these)
directions...
First, brown your butter: heat slowly in a pan over medium heat. Whisk as you go and watch carefully. After a few minutes, the butter will foam and then recede, turning a carmel brown color. It will smell sort of nutty. Don't let it burn, but be sure it's actually browned (not just melted) - when you pour it out of the pan and into a bowl to cool, it should be a rich, burnt sienna color. Let the butter fully cool before you start - 20 minutes on the counter should do it.
Meanwhile, mix together all your dry ingredients (flour, espresso powder, baking soda and salt). In a separate bowl, combine your brown butter and sugars thoroughly. Add the egg, yolk, yogurt, and vanilla and stir until smooth. Gradually mix in your dry ingredients about 1/2 cup at a time. Stir in the toffee bits and chocolate chips until evenly distributed. Taste liberally. Add more espresso powder if you're into that sort of thing, but be sure to mix well.
Stick the whole shebang in the fridge for at least an hour. Preheat the oven to 375. Roll loosely rounded balls of dough (make sure you get all those chocolate chips in there - sometimes I'll dot the tops with a few extra) and drop 2-3 inches apart on your pan. Bake for 8-10 minutes. The cookies should look slightly undercooked in the middle, but they will set up within a few minutes of removing from the oven.
Enjoy!