Preheat oven to 350' F.
In mixing bowl, add melted butter and sugar. Mix. Add eggs and vanilla. Mix.
Melt 1/4 cup white chocolate chips and add to sugar mixture. Stir until well incorporated.
Add salt, flour, remaining white chocolate chips 1/2 cup), and 1/4 cup sprinkles. Mix only until combined.
Pour into 9x9 or 7x11 inch pan lined with parchment paper. Sprinkle remaining 1/4 cup sprinkles on top.
Bake at 350' F for 30 minutes or until toothpick in center comes out clean. If using a glass pan, it may take up to 5 additional minutes to bake.