Preheat oven to 350 degrees and spray 9 x 13 baking pan with cooking spray.

Beat eggs and sugar in large mixing bowl for 5 minutes. This is the most important step. Please do not skip. The mixture should almost double in size and will thicken.

Add butter and vanilla and continue to mix.

Mix in flour until well combined.

Stir in cranberries.

Spread batter in baking pan.

Bake 40 - 45 minutes or until toothpick inserted comes out clean.

Let cool before cutting. Enjoy!