Preheat oven to 350 degrees. Spray a 13×9 inch metal baking pan with flour added cooking spray or grease using your preferred method.Sift together flour, baking soda and salt; set aside.Beat sugar and eggs together for 1 ½ minutes using high speed of electric mixer. Beat in oil and vanilla; when well mixed, beat in the melted chocolate and beets.
Add the flour mixture to the egg mixture and stir until well mixed. The batter might seem a little lumpy from the beet puree, but that’s okay.
Pour the batter into the pan and bake on center rack of oven for 25 minutes or until cake tests done. To test for doneness, insert a wooden pick or skewer in center. It should come out clean or with a moist crumb or two. The cake might seem almost too moist, but it firms up as it cools and mellows out.
Let cool completely. If you have the time, let sit over night and serve the next day.
