Preheat the oven to 350°F and line z 9x13 pan with parchment paper or tinfoil and spray with non-stick spray.
In another large bowl, using an electric mixer at medium speed, beat together the butter, and sugars about 2 minutes and is smooth.
Add the eggs and vanilla and mix on low speed until mixed in.
Sift the flour, baking soda and salt over the wet mixture and mix together until just incorporated. Do not keep mixing - do not overmix.
Add chocolate chips, vanilla chips and sprinkles in, stirring with a wooden spoon, again no overmixing, just until incorporated. Dough will be very thick.
Spread thick cookie dough out evenly by dropping spoonfuls onto the baking sheet and spread out with fingers or it helps to spray a rubber spatula with non-stick spray. Dough will spread out while baking, so you don't have to get the corners and edges perfect.
Sprinkle some extra chocolate chips and sprinkles to the top of the blondies.
Bake for 20 to 25 minutes or until golden brown. Cool in pan on wire rack.
After bars have cooled, lift the parchment paper out and cut the bars.Makes 12-15 dozen bars depending how big you make them. Enjoy the party!