Step 1

Preheat oven to 350°F. Line a 9x13 pan with foil and lightly grease the foil.

Step 2

Using a stand mixer fitted with the paddle attachment, combine granulated sugar, flour, baking powder, and salt. Add orange zest, butter, egg, and vanilla. Beat on low speed until the butter is evenly distributed in small pieces and the mixture is crumbly.

Step 3

Dump a little more than half of the mixture into the bottom of the prepared pan (reserving the remaining amount, about 2 1/2 cups, for the topping). Use your hand or the bottom of a measuring cup to evenly press the dough into the pan.

Step 4

Gently stir together all ingredients until well incorporated.

Step 5

Scoop the cranberries onto the crust, making sure the cranberries and juices are evenly distributed over the crust. Crumble the reserved dough over the top of the berries.

Step 6

Bake for approximately 45-50 minutes, until the top is light golden brown and the cranberries are bubbling in some spots. Transfer pan to a rack to cool completely.

Step 7

Whisk all ingredients until smooth. Adjust the consistency by adding more powdered sugar to thicken or more milk to thin. Drizzle over the cooled bars.