Preheat oven to 350 degrees Fahrenheit. Wash the strawberries, remove the stems, and slice approximately ¼ inch thick. Spread half of the sliced berries on a parchment lined baking sheet in a single layer. Place in the oven to roast for 25 minutes. Remove from the oven and set aside to cool.
While the strawberries are roasting, add the remaining sliced strawberries, lemon juice, 2 tablespoons of the sugar, and cornstarch to a small sauce pan. Let mixture come to a rolling boil over medium high heat, stirring occasionally. Once boiling, turn to low heat and let it slowly bubble for 10 more minutes until syrup is thickened and the strawberries are soft. Remove from heat and pour into a bowl to cool.
Combine the flour, baking powder, salt, 2 tablespoons of the sugar, and lemon zest in a large bowl. In a separate small bowl whisk together the egg yolks, melted butter, vanilla, and milk. Place egg whites in a medium bowl and use an electric mixer on medium speed to whip until stiff peaks form, about 2 minutes.
Add wet ingredients to dry ingredients and gently stir until combined. Mixture will be slightly lumpy. Stir in the roasted, cooled strawberries. Using a spatula, gently fold egg whites in to the pancake batter until evenly combined. Be careful not to over mix.
Turn an electric griddle to 375 degrees or heat a large nonstick skillet to medium heat on the stove. Spray with nonstick cooking spray. Use a 1/3 measuring cup to pour batter onto the hot griddle or pan. Wait till bubbles start to form and pop before flipping strawberry pancakes to the other side. Allow each side to become golden brown.
Place a pancake on a plate and spread with a heaping spoonful of whipped topping and strawberry sauce. Place two more pancakes in the same manner. Top with a dollop of whipped topping and more sauce. Enjoy!