HEAT oven to 300ºF. Spray two 9 x 2-inch round cake pans with no-stick cooking spray. Line bottoms with rounds of wax paper or parchment paper; spray again.
COMBINE chocolate chips and hot coffee in medium bowl. Let mixture stand, whisking occasionally, until chocolate is melted and mixture is smooth. Whisk together sugar, flour, cocoa powder, baking soda, baking powder and salt in large bowl.
BEAT eggs in bowl of electric mixer until thick and yellow, about 3 to 5 minutes. Slowly add oil, buttermilk, vanilla and melted chocolate mixture, beating until well combinedl. Add dry ingredients; beat on medium speed until just combined. Divide batter between prepared pans.
BAKE 40-45 minutes in middle of oven or until a toothpick inserted in center comes out clean. Cool in pans on racks 30 to 45 minutes. Run a thin knife around edges of pans. Invert layers onto racks. Carefully remove wax paper. Cool completely. Use your favorite frosting or try the Glossy Chocolate frosting(as seen in the picture) that I have also posted.