In a large bowl, whisk your eggs and sourdough discard together well. Slowly add in your butter and continue whisking. Once smooth, add in your sugars and vanilla, whisking to combine all the wet ingredients well.
In a medium bowl, combine your remaining ingredients, sans raisins. Add this dry mix to the wet mix and stir well. Before fully combined, add in your raisins and use your hands to press and mix the dough until no dry flour bits.
Cover and place this in the fridge for 2 hours at least before baking.
If you place in the fridge for longer, such as overnight, it can yield a fluffier cookie. This can be mostly fixed, see notes.
Preheat your oven to 350 degrees.
Take a tablespoon of cookie dough and place onto your parchment paper lined cookie sheet. I usually fit 12 cookies per sheet.
Bake for 8-10 minutes.
Once you remove the tray from the oven, drop or bang the bottom of the tray with the hot cookies onto a heat safe area (wood cutting board, stovetop, etc). This will help remove extra air in the cookies yielding a doughy more chewy cookie.
Once cooled, store at room temperature for 7-10 days.