Preheat oven to 350 degrees and lightly coat a 9x13 baking dish with cooking spray.
Transfer drained beets to a food processor. Pulse until finely ground into a paste.
In microwave, heat unsweetened until melted. Add to food processor and pulse until combined with beets. Transfer mixture to the bowl of a stand mixer fitted with a paddle attachment or a large mixing bowl.
Sift together flour, baking soda and salt and set aside. Add sugar, eggs and oil to beet and chocolate mixture. Blend until fully combined. Slowly add flour mixture. Blend until a cake batter consistency.
Evenly spread into the bottom of prepared 9x13 inch baking dish. Bake for 25-30 minutes, or until the cake passes the toothpick test.
Remove and allow to cool. You can serve warm or cover tightly with aluminum foil and store for up to 4 days. Directly before serving, garish with powdered sugar. Enjoy!
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