In a medium saucepan over low heat, combine the sweetened condensed milk, chocolate chips, and butter. Stir continually until the mixture is smooth and glossy, about 5 minutes.

Once your fudge base is ready, pour it into a parchment-lined 8-inch square baking pan. Use a spatula to spread it evenly, creating a smooth surface. Set aside to cool slightly, around 10 minutes.

In a blender or food processor, combine the fresh strawberries, powdered sugar, and lemon juice. Blend until smooth, then pour this mixture over the cooling fudge.

Using a toothpick or knife, gently swirl the strawberry mixture into the fudge. Aim for a marbled effect without fully blending the two together—this creates those beautiful pink swirls!

Place the pan in the refrigerator to chill for at least 2 hours, or until the fudge is firm to the touch. This will give it the perfect texture for slicing.

Once set, lift the fudge out of the pan using the parchment paper. Cut into squares and serve to your eager guests.