Preheat oven to 350 degrees
With a mixer, beat the eggs with sugar until slightly thickened and light in color. The mixture should almost double in size. The eggs work as your leavening agent in this recipe so DO NOT skip this step. This will take about 3-4 minutes.
This mixture should form a ribbon when you lift the beaters out of the bowl.
Add the butter and vanilla. Mix two more minutes.
Stir in the flour until just combined.
Add the cranberries and gently fold by hand the cranberries into the batter. The batter will be very thick.
Spread in a buttered and floured 9x13 pan (or two 8 inch baking pans if you want to share).
Bake for 35-40 mintues or until very lightly browned and toothpick inserted near the center of the cake comes out clean.
Let cool completely before lightly sifting powdered sugar on top.