Preheat the oven to 350 degrees.

Combine the butter and white chocolate chips in a bowl. Microwave in 30 seconds intervals, stirring after each interval, until the mixture is smooth.

Pour into a large bowl and add the sugar. Mix well.

Mix in the salt, vanilla, and eggs and mix until combined.

Stir in the flour and baking powder.

Spread into an 8 x 8 pan sprayed with baking spray.

Bake for 28-30 minutes. Remove from oven and cool completely.