Preheat your oven to 350 degrees F. Line an 18"x13" pan with parchment paper, letting the ends hang over the edge of the pan.

In a medium-sized pot, heat the sugars, butter, and milk until it’s steaming. Remove the pot from the heat and add the chocolate. Let the chocolate sit for 3 minutes then stir until it melts.

Once the chocolate cools slightly and is warm to the touch, whisk in the eggs and vanilla.

Add the flour, baking soda, and salt to the pot and stir just until it’s mixed in.

Pour the batter into the prepared jelly pan, spreading it evenly to the sides.

Bake for 12-15 minutes, or until it has puffed up slightly and the top looks dry.

Remove the pan from the oven and gently press down on the brownie to flatten it, using a paper towel if it’s too hot on your hands.

Let the brownie cool completely, then use the parchment paper to remove it from the pan.

Cut the brownie in half, laying one half on a parchment paper-lined baking sheet.

Use your stand mixer or electric beaters to whip the ice cream for about 10 seconds until it’s soft and easy to spread.

Spread the soft ice cream over the brownie on the baking sheet.

Top with the other half of the brownie and place the baking sheet in your freezer for at least 2 hours.

Once frozen, cut it into smaller ice cream sandwiches.

If using sprinkles, mini chocolate chips, or nuts, dip the edges of the sandwiches into them.

Wrap each sandwich individually and store them in your freezer.