Instructions

• Preheat the oven to 350°F (175°C). Line a 9x13-inch baking pan with foil for easier cleanup (or use a similar-size pan), and spray the foil with cooking spray; set the pan aside.
• In a large mixing bowl, add the cake mix, 3 large eggs, 1 cup water, 1/3 cup vegetable or canola oil, 1/4 cup Greek yogurt, 2 teaspoons cinnamon, and 2 teaspoons vanilla extract.
• Using a handheld electric mixer, beat the mixture on high for about 4 minutes, or until blended and smooth. Stop as needed to scrape down the sides and bottom of the bowl.
• Pour the batter into the prepared pan and spread it into an even layer.
• Bake for 20 to 25 minutes, or until the cake is set and a toothpick inserted in the center comes out clean or with a few moist crumbs.
• Remove the cake from the oven and let it cool in the pan about 30 minutes on a wire rack.
• Using the blunt end of a wooden spoon (or similar utensil), poke evenly spaced holes across the surface of the cake, pushing nearly all the way to the bottom. Aim for about 40–50 holes or roughly 1 inch apart.
• Slowly and evenly drizzle the 14-ounce can of sweetened condensed milk over the cake surface, allowing it to seep into the holes. Pour gradually so the milk has time to absorb.
• Evenly spread the thawed 8-ounce container of whipped topping over the surface of the cake.
• Cover the cake and refrigerate until thoroughly chilled, about 3 hours.
• Just before serving, sprinkle additional cinnamon for garnish. Store the cake airtight in the refrigerator for 5 to 7 days.