Step 1

In a medium saucepan, warm up the half-and-half over medium heat, stirring, until it's warm but not hot. Pour it into a blender with the white rice and briefly blend the mixture on high speed to break up some of the grains and release their flavor. Allow the mixture to steep for at least one hour.

Step 2

Strain the liquid through a nut milk bag or cheesecloth and discard the rice. Stir in the Rumchata and return to the saucepan on medium heat. Add the vanilla extract.

Step 3

Vigorously whisk together the egg yolks and sugar. When the half-and-half just reaches a simmer, slowly pour it into the egg yolks while whisking. Then return the entire mixture back to the saucepan and turn the heat to low. Add the cinnamon sticks.

Step 4

Stir constantly for several minutes until it begins to thicken. When it coats the back of a spoon or spatula so that you can draw a line with your finger, remove from the heat.

Step 5

Allow the base to cool slightly then pour into a bowl. Cover with plastic wrap, pushing the plastic directly against liquid to prevent a skin from forming. Chill for at least 4 hours or overnight, until very cold. Remove the cinnamon sticks and discard.

Step 6

Prepare in an ice cream machine according to manufacturer instructions. Before serving, top with fresh grated cinnamon.