Preheat your oven to 350°F (175°C) to ensure it reaches the correct temperature for baking the crust and filling.

In a large mixing bowl, combine softened butter, sugar, and flour until a crumbly dough forms. Press the dough evenly into a greased 9x13-inch baking pan.

Bake the crust in the preheated oven for 20 minutes or until the edges turn golden brown. This will form the base layer for the lemon filling.

In another mixing bowl, whisk together the eggs, sugar, flour, lemon juice, and lemon zest. Ensure the mixture is smooth and well combined.

Carefully pour the lemon filling over the baked crust. Spread it evenly to cover the entire crust.

Return the pan to the oven and bake for an additional 30 minutes or until the filling is set and lightly golden.

Allow the lemon bars to cool completely in the pan. Cooling helps the filling to set properly.

For best results, refrigerate the bars for at least an hour before cutting into squares and serving.

Store any leftover lemon bars in an airtight container in the refrigerator for up to a week.

For longer storage, wrap individual squares in plastic wrap and freeze for up to three months. Thaw in the refrigerator before serving.