Place your metal bowl from the electric mixer and the whisk attachment (or a regular metal bowl and the beaters) in the freezer for 10-15 minutes.
Make sure that the heavy whipping cream and creamer are both cold, straight from the fridge.
Add the heavy whipping cream and hazelnut creamer into the cold mixing bowl. Starting at low speed, start whisking, gradually raise to speed to high. Beat until stiff peaks appear (don't walk away far so you don't over-mix.)
Using a rubber spatula, very slowly pour in the sweetened condensed milk while folding the whipped mixture. Keep folding, carefully, the condensed milk into the whipped mixture, making figure 8, just until there are no more streaks and the mixture is smooth.
Carefully, transfer the mixture into a large, airtight container. (I used a large, airtight tupperware and sealed it with saran wrap, just in case.)
Freeze for at least 5-6 hours, depending on the container.