Preheat oven to 325F
Line 8 inch square pan with parchment paper (or grease pan)
In a microwave safe bowl--melt butter with chocolate chips. Mix until they're smooth. Set aside to cool while you do the next steps.
Combine both of the sugars and eggs in a separate - do not over-mix.
In a medium bowl combine flour, cocoa powder, salt and baking soda.
Slowly pour and whisk chocolate mixture into the eggs and sugar. A little at a time, add dry ingredients into this mixture. Fold everything together with a spatula until just barely combined.
Pour the brownie batter into pan and bake for about 40 minutes. Remove the brownies from oven and let cool for about 30 minutes. You can prepare the chocolate sauce while they cool!
Increase oven temp to 450F
Combine all Chocolate Sauce ingredients in small bowl. (Sauce should be similar to a chocolate syrup consistency. Add your tablespoons of milk slowly until you get the right texture! You might not need the 3rd tbsp) Spread most of it on top of the brownies, set aside the rest to drizzle on top of marshmallows later.
Cover the sauce layer in mini marshmallows. You can add as many or as little as you like! (We covered the top!) Place brownies back into the oven for 2-5 minutes until the marshmallows are toasted/have begun to brown.
Remove them from the oven and allow them to cool for another 10-15 minutes in the pan. Drizzle with the rest of chocolate sauce. Enjoy!
