Line a 9x9-inch baking dish with parchment paper.
In a microwave-safe bowl, combine 3 cups of semi-sweet chocolate chips and the can of Eagle Brand Sweetened Condensed Milk. Microwave in 30-second intervals, stirring in between, until melted and smooth.
Stir in a dash of salt, 1/4 cup of creamy peanut butter, and 1 1/2 teaspoons of vanilla extract until well combined.
Fold in 1 cup of chopped mini peanut butter cups, 1/2 cup of peanut butter chips, and 1/2 cup of semi-sweet chocolate chips.
Pour the fudge mixture into the prepared baking dish. Spread it evenly and tap the dish on the counter to remove air bubbles.
Refrigerate for at least 3 hours, or until completely set.
Remove from the dish using the parchment paper, cut into squares, and serve.
