Preheat your oven to 350°F (175°C) and grease an 8×8 inch baking pan or line it with parchment paper.

In a large mixing bowl, whisk together the all-purpose flour, baking powder, and salt.

In a separate bowl, cream the unsalted butter and granulated sugar together until light and fluffy.

Add the eggs one at a time and mix well after each addition, then stir in the vanilla extract.

Gradually fold the dry ingredients into the wet batter until just combined.

Gently fold in the fresh cranberries and white chocolate chips if using.

Spread the batter evenly into the prepared pan and bake for 35-40 minutes or until a toothpick comes out clean.

Let the cake cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely.

For the frosting, beat the softened cream cheese and unsalted butter until smooth, then gradually add powdered sugar and vanilla, adjusting the consistency with milk or cream.

Once the cake is completely cooled, frost it generously with the cream cheese frosting and garnish if desired.