Heat your oven to 350°F and grease a 9x13 inch baking dish (or similar size) with butter or cooking spray, making sure to coat the bottom and sides evenly. This prevents sticking and ensures even browning on the cake edges.

In a large bowl, combine the strawberry cake mix, greek yogurt, water, and lemon zest. Mix on medium speed for about 1 minute until the batter is smooth and well combined—don't overmix, as this can make the cake tough. Pour the batter into your prepared pan and bake for 25-35 minutes, until a toothpick inserted in the center comes out clean or with just a few moist crumbs. The lemon zest adds a bright note that complements the strawberry flavor beautifully.

Remove the cake from the oven and let it cool in the pan for at least 15-20 minutes before frosting. This allows the cake to set and become stable enough to support the topping without falling apart. For best results, I like to let it cool to room temperature before adding the frosting.

In a medium bowl, whisk together the instant vanilla pudding mix, whole milk, and vanilla extract for about 1-2 minutes until the mixture thickens to a mousse-like consistency. The pudding will continue to thicken slightly as it sits, so don't overmix. Gently fold in the thawed whipped topping using a spatula until fully combined, being careful not to deflate the whipped topping—you want to maintain that light, fluffy texture.

Fold the finely diced fresh strawberries into the pudding frosting mixture from Step 4 until evenly distributed. Spread the frosting generously over the cooled cake from Step 3, working from the center outward for even coverage. Top with additional fresh strawberry slices if desired for a beautiful presentation. I prefer to add the strawberries into the frosting rather than just on top—it creates pockets of fresh fruit throughout each bite.