Scottish Shortbread with Ghirardelli Chocolate Squares

Ingredients

• Shortbread:
• 2 1/2 cups all-purpose flour
• 1/4 teaspoon salt
• 1/2 cup granulated sugar
• 1 cup unsalted butter, softened, plus more as needed
• Chocolate Frosting:
• 1 bag (10 oz) Ghirardelli 60% Cacao Bittersweet Chocolate Baking Chips
• 3 tablespoons Ghirardelli 100% Unsweetened Cocoa
• 1/4 cup boiling water
• 3/4 cup unsalted butter, softened
• 1/4 cup confectioner’s sugar
• Pinch of salt