Preheat oven to 325 degrees F.

Line 2 (12 by 14-inch) sheet pans with parchment or buttered waxed paper.

In a medium sized bowl, combine the first 5 ingredients and sift onto a piece of parchment or waxed paper. Set aside.

In an electric mixer fitted with a paddle, beat eggs for 1 minute. Add sour cream and chocolate syrup and mix to combine. With mixer on low speed, gradually add the dry ingredients until incorporated. Add melted butter and mix until fully incorporated.

Spread batter evenly onto the 2 sheet pans. Bake cakes for 10 to 12 minutes, or until a toothpick inserted in the center comes out clean. Let cakes cool completely.

Using a serrated knife, cut off the top crust from the cakes. Freeze the cakes for 5 minutes.

Spread softened ice cream onto 1 cake. Place second cake on top. Freeze until hardened. Cut into 3-inch squares when ready to serve.