Preheat oven to 350 degrees

Line an 8x8 baking pan with parchment paper - set aside

Cream butter, sugar & salt in mixer on medium high until well blended & fluffy

Add in vanilla & then flour - beat until crumbly

Press 3/4 of the dough into a flat layer in bottom of prepared pan

Top with semi-sweet & white chocolate chips & M&M's

Sprinkle remaining dough over the top & lightly press down

Add hearts

Bake approx 45 minutes or until golden on top

Cool to room temperature on wire rack

Remove by lifting out by parchment

Cut unto squares & enjoy