In a mixing bowl, cream together the softened butter and light brown sugar until it's light and fluffy. Add the vanilla extract and mix well.

Gradually add the all-purpose flour and mix until it forms a cookie dough-like consistency. Fold in the milk chocolate chips and white chocolate chips.

Line a square baking dish (approximately 8x8 inches) with parchment paper, leaving some overhang for easy removal later. Press half of the cookie dough mixture evenly into the bottom of the dish.

In a separate bowl, mix the condensed milk and melted dark chocolate until well combined. Pour this chocolate mixture over the cookie dough layer in the baking dish, spreading it evenly.

Take the remaining cookie dough mixture and crumble it over the top of the chocolate layer. Gently press it down.

Allow the fudge to proof at room temperature for about an hour to set.

After proofing, refrigerate the fudge for at least 4 hours or until it's completely firm.

Once set, use the parchment paper overhang to lift the fudge out of the dish. Cut it into 16 squares.

Serve and enjoy your delicious Cookie Dough Fudge!