Preheat your oven to 325°F (163°C). Line your baking pan with parchment paper, leaving some overhang on the sides for easy lifting.
In a large mixing bowl, beat together the softened butter, powdered sugar, and granulated sugar until light, fluffy, and creamy, about 3-4 minutes with an electric mixer.
Mix in salt, orange zest, orange juice, and vanilla extract until combined and fragrant.
Gradually add the all-purpose flour to the wet ingredients. Mix slowly until just combined. The dough should be soft and slightly crumbly.
Gently fold in the chopped dried cranberries evenly, being careful not to overmix.
Transfer the dough into the prepared pan and press it down firmly and evenly. Smooth the surface for even baking.
Bake for 25-30 minutes until the edges are just turning golden and the center is set but still pale.
Allow the shortbread to cool completely in the pan on a cooling rack. Use the parchment overhang to lift it out, then slice into even rectangles or squares.
Serve alone or with tea or coffee. Enjoy your Cranberry Orange Shortbread Slices!