Preheat oven to 375F and line a baking sheet with parchment paper on non-stick baking mats.
In a stand mixer or with an electric mixer, cream together the butter, brown sugar and white sugar until well combined and slightly fluffy. (Since there is brown sugar it won’t fluff up as much as if it was just white sugar)
Add in the milk and vanilla and mix until fully combined.
In a medium sized bowl whisk together the flour, cocoa powder, baking soda, baking powder and ¼ teaspoon salt.
Slowly add the dry ingredients into the wet ingredients, until fully combined.
Using a wooden spoon fold in the chopped dark chocolate or non dairy chocolate chips.
Using an ice cream scoop or spoon, scoop out approximately 2-inch balls of batter and place on the prepared lined baking tray. Using your hand lightly squish the dough down just slightly and sprinkle on a couple pieces of coarse sea salt if using.
Continue until the baking tray is full - place cookies approximately 2 inches apart as they will spread quite a bit.
Bake the cookies for 17-19 minutes until they are slightly crispy on the bottom. Remove from oven and allow to sit on the tray for 5 minutes and then remove to a cooling rack. Cookies will be slightly crispy once fully cooled. If you prefer a softer cookie reduce the cooking time by about 2 minutes less.
Once cookies are cool, scoop out the ice cream and place on 1 cookie and top the sandwich with another cookie pressing down slightly.
Serve and enjoy!
*If you want to make these cookies to eat and not for ice cream sandwiches, replace the ½ cup brown sugar with ½ cup white sugar for a total of 1 cup of white sugar and no brown sugar. This will cause the cookies to become fluffier and thicker while they cook.
** We prefer a slightly crispier cookie for our sandwiches as the ice cream causes them to soften. If you like a softer cookie, reduce the baking time by about 2 minutes.