Prepare the lemon grass: Remove the woody outer leaves.

Slice the tender inner stalk of lemon grass crosswise.

Combine sliced lemon grass, peanuts, garlic, ginger, lime rind, lime juice, anchovy paste, sugar, and red pepper flakes in a blender.

Add coconut milk to the blender.

Puree the mixture until smooth.

Transfer the mixture to a food processor.

Add basil and cilantro to the food processor.

Puree the mixture until well combined.

Season the sauce to taste with salt.

Pack the sauce into half or cup portions.

Freeze for later use.