Peel the potatoes and cut into eighths. Place potatoes in a pan with garlic and cover with water. Bring to boil and simmer until very tender when pierced with a fork, about 15 to 20 minutes.
In a separate pan, combine butter, 1/3 (45-50 ml) of the milk and peppers. Bring to a simmer for 1 minute. Puree the milk and chile mixture in a food processor.
When potatoes are cooked, drain well. Place potatoes in bowl of kitchen mixer and begin whipping at high speed with the whip attachment. Gradually add remaining milk and chile mixture, whipping between each addition.
Note: The final consistency of the potatoes depends on the how well drained they are. It is advised to add only enough of the puree to achieve a smooth, light and creamy-textured mashed potato.