Step 1: Preheat the Oven
1. Preheat Oven: Preheat your oven to 350°F (175°C). Grease and line a 9×13-inch baking pan with parchment paper, leaving some overhang for easy removal.

Step 2: Prepare the Base
1. Cream Butter and Sugars: In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
2. Add Eggs and Vanilla: Beat in the eggs one at a time, then mix in the vanilla extract.
3. Combine Dry Ingredients: In a separate bowl, whisk together the flour, baking powder, and salt.
4. Mix Together: Gradually add the dry ingredients to the wet mixture, mixing until just combined. Gently fold in the chopped cranberries.

Step 3: Bake
1. Spread in Pan: Pour the batter into the prepared baking pan and spread it evenly.
2. Bake: Bake in the preheated oven for 30–35 minutes, or until a toothpick inserted into the center comes out clean. The edges should be lightly golden.
3. Cool: Allow the bars to cool in the pan for about 10–15 minutes, then lift them out using the parchment paper and transfer to a wire rack to cool completely.

Step 4: Prepare the Glaze
1. Mix Glaze Ingredients: In a small bowl, whisk together the powdered sugar, milk, and vanilla extract until smooth. Adjust the consistency by adding more milk or powdered sugar as needed.

Step 5: Glaze and Serve
1. Glaze the Bars: Once the bars are completely cool, drizzle the glaze over the top. Allow it to set for a few minutes.
2. Cut and Serve: Cut into squares or bars and serve.