Turn the piece upside down. Tack on an edge guide for your circular saw. Extra care must be taken as you cut the backsplash as the cut comes around the corner. I usually cut the backsplash first.. The fall off must either be small or well supported to prevent it breaking free at the end of the cut with the potential to damage the finish.
(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net