Preheat & Prep: Preheat the oven to 350°F and lightly coat a 9×13-inch casserole dish with nonstick cooking spray.
Mix the Batter: In a large mixing bowl, combine the cake mix, eggs, vegetable oil, and vanilla extract. Stir until fully blended.
Add the Sweetness: Gently fold in the Easter M&M candies and chocolate chips, distributing them evenly.
Spread & Bake: Evenly spread the batter into the prepared baking dish and bake for 20-25 minutes, or until the top is golden brown and set.
Cool & Serve: Allow the bars to cool completely before slicing into squares. Enjoy!