Preheat oven to 350 F. Sift the dry ingredients into a large mixing bowl, set aside.
Place eggs, sour cream, oil, and vanilla into a separate mixing bowl. Beat with a hand mixer until well incorporated.
Place the water into a small saucepan, and heat until just before boiling point. While water is heating, place the chocolate chips into a microwave safe bowl. Heat for 30 second intervals, stirring in between until melted completely.
Add the bowl of wet ingredients to the dry ingredients, along with the hot water and melted chocolate. Beat on low until well incorporated, increase speed to medium-high and mix until smooth, 3-4 minutes.
Coat 4, 6 inch cake pans with vegetable oil spray. Use a generous and even amount on all pans. Bake in preheated oven for 30-35 minutes, or until a toothpick inserted comes out clean. Cool for at least 25 minutes before removing cake from pans. Place cake layers on wire racks until completely cool. Wrap in plastic wrap and preferably chill overnight before decorating (this will prevent excess crumbs in your frosting).