Using an electric mixer, beat the eggs with the sugar until slightly thickened and light in color, about 5-7 minutes. The mixture will almost double in size. Pay attention to this step - the eggs are the leavening agent in this recipe.
Add in the softened butter and vanilla extract. Mix another 2 minutes.
Stir in the flour, by hand, until just combined - do not over mix!
Add the cranberries and chocolate chips. Gently stir until mixed throughout.
Bake for 40-50 minutes, or until top is a light golden brown and a toothpick inserted near center of cake comes out clean.