Start by partially melting your butter about halfway. Add in the brown sugar and cream it until fluffy.
Add in one large egg and beat until incorporated. Then add in your sourdough discard. Beat for 2 minutes.
Add in vanilla, salt, baking soda, and flour, and mix until combined.
Then, add in 2 cups worth of chocolate. I used 1 cup of semi-sweet chocolate chips, ½ cup of mini semi-sweet chocolate chips, and ½ cup of a good chocolate bar chopped into chunks. Mix this in really well to make sure there's chocolate throughout.
Scoop out 3-ish Tbsp portions (using a cookie scoop, preferably, or eyeball it). Chill the dough balls for 1 hour uncovered, or up to 48 hours uncovered.
Preheat your oven to 350ºF. Set 8 dough balls on a lined baking sheet, and bake for 12 to 15 minutes, depending on your preference for doneness.
Allow them to cool for 5 minutes on the pan before moving to a cooling rack. Note that slightly underdone cookies make fall through the grates of your cooling rack, so you might try cooling on parchment paper on the counter instead.
Notes
Note: You can freeze the cookie dough in an airtight container for up to 6 months. To bake from frozen, let them thaw on your baking sheet for 30 minutes before going into a preheated oven.