In a sealable container or mixing bowl, combine the milk and raisins, and then place in the refrigerator overnight, or for at least 4-5 hours. (You can also cook over medium-low heat on the stove-top, stirring frequently, for 30 minutes). Note: this process will work to naturally thicken and sweeten the milk. You can use soaked raisins as a topping for oatmeal or to sweeten smoothies so as not to waste, if you'd like).
Strain the raisins from the milk using a fine mesh strainer; discard the raisins.
In a saucepan over medium heat, combine 1 1/2 cups of the homemade condensed milk, additional milk, pure maple syrup, and arrowroot starch.
You can transfer this base creamer recipe to a sealable container and store in the fridge until ready to use. As is, it keeps for up to 5 days in the refrigerator.
Add additional vanilla extract to base creamer recipe and stir to combine.
Transfer this to a sealable container and store in the fridge until ready to use.
Add cocoa powder, espresso powder, and peppermint extract to base creamer recipe and stir to combine.
Transfer this to a sealable container and store in the fridge until ready to use.
Add hazelnut extract to base creamer recipe and stir to combine.
Transfer this to a sealable container and store in the fridge until ready to use.
Add vanilla extract and cocoa powder to base creamer recipe and stir to combine.
Transfer this to a sealable container and store in the fridge until ready to use.
Add vanilla extract and cinnamon to base creamer recipe and stir to combine.
Transfer this to a sealable container and store in the fridge until ready to use.