Soft, buttery sugar cookie bars topped with creamy vanilla buttercream and rainbow sprinkles. Perfect for back-to-school treats, bake sales, or any day that needs a little extra color.
Use rainbow jimmies (long sprinkles) not nonpareils to prevent color bleeding. Do not overmix dough. Cool bars completely before frosting. For clean cuts, refrigerate frosted bars 20-30 minutes before cutting. Bars taste even better the next day.
Keywords: sugar cookie bars, rainbow sprinkles, back-to-school treats, easy dessert, cookie bars, buttercream frosting