Melt white chocolate in the microwave gently on 70% power until smooth.
Pour into a mixer with the butter and beat smooth.
Add sugar.
Add eggs.
Add salt and vanilla.
Add flour.
Gently fold in sprinkles.
Pour batter into 8x8 pan lined with nonstick foil.
Top with more sprinkles.
Bake at 350 for 25-28 minutes.
Let cool before cutting