Step 1: Prepare the Cookie Dough Layer

1. Cream Butter and Sugar: In a medium mixing bowl, cream the softened butter, granulated sugar, and brown sugar together using an electric mixer on medium speed until smooth and creamy.
2. Add Milk and Vanilla: Beat in the milk and vanilla extract until fully combined.
3. Incorporate Flour: Gradually add the heat-treated flour, mixing on low speed until a soft dough forms.
4. Add Chocolate Chips: Fold in the mini chocolate chips using a spatula.
5. Set Aside: Set the cookie dough aside while you prepare the fudge layer.

Step 2: Make the Fudge Layer

1. Melt White Chocolate Chips: In a medium saucepan, combine the sweetened condensed milk and white chocolate chips. Heat over low heat, stirring constantly, until the chocolate chips are melted and the mixture is smooth.
2. Add Vanilla: Remove from heat and stir in the vanilla extract.

Step 3: Assemble the Fudge

1. Line the Pan: Line an 8×8-inch baking pan with parchment paper, leaving an overhang for easy removal.
2. Layer Cookie Dough: Press the cookie dough evenly into the bottom of the prepared pan.
3. Pour Fudge: Pour the melted white chocolate fudge mixture over the cookie dough layer, spreading it evenly with a spatula.
4. Add Garnishes: Sprinkle additional mini chocolate chips or other garnishes over the top, pressing them gently into the fudge layer.

Step 4: Chill and Set

1. Refrigerate: Place the pan in the refrigerator and chill for 2–4 hours, or until the fudge is fully set.
2. Cut into Squares: Once set, lift the fudge out of the pan using the parchment overhang. Cut into 16–20 squares using a sharp knife.