Reducing Sugar and Butter in a Recipe?

I found this recipe for mini pear-tarts in Mason jar lids. http://www.fatgirltrappedinaskinnybody.com/2011/09/mini-pear-tarts-in-mason-jar-lids/

The above recipe calls for all this sugar. If I use less sugar and butter, will it mess up this recipe?

By Robyn from TN