Prepare a bowl set into a large bowl filled with ice and water and set aside.
Combine the condensed milk, cream, pumpkin puree and cloves in a medium heavy-bottomed saucepan over medium heat. Cook, whisking, until just below simmering. Place the egg yolks in a bowl and whisk to combine. Slowly add some of the warm cream mixture (about 1/4 cup) to the yolks, whisking constantly (this is called tempering and will prevent the yolks from curdling). Then, whisk the tempered egg yolk mixture into the saucepan. Remove from the heat and cool down by pouring the mixture into the prepared bowl. Stir occasionally, until completely cooled down.
Place the mixture into a blender along with the sugar, bourbon and ice cubes. Blend until smooth. To serve, fill rocks glasses with ice and pour the eggnog over.