Place the semi-sweet chocolate chips, mini marshmallows, 1/2 can sweetened condensed milk, and salt in a microwave safe bowl.
Microwave in 45-second increments, mixing each time. Once fully melted, fold in 1 tsp vanilla extract.
Grease a 9x9 square dish.
Pour the chocolate fudge batter into the dish and smooth out the top with a rubber spatula.
Combine the white chocolate chips and remaining 1/2 can of sweetened condensed milk in a microwave safe bowl
Microwave in 45-second increments, mixing each time.
Once fully melted, mix in the pumpkin, pumpkin pie spice, and 1 tsp vanilla until fully combined.
Pour the pumpkin fudge on top of the chocolate fudge. Smooth the top with a rubber spatula.
Refrigerate 3-4 hours, until set.
Cut into squares and serve. Refrigerate any uneaten chocolate pumpkin spice fudge.