Heat the milk, water and sugar in a large saucepan. Cook the cleaned corn on the cob for 20 minutes over medium heat. Remove from the milk and drain well.
For the butter, peel the lime thinly with the peeler, finely chop the peel. Halve, core and finely chop the chilli pepper. Mix the butter with the lime zest, chilli pepper and a little salt.
Grill the corn on the cob for 5-8 minutes. Remove from the grill and serve with 1/4 of the lime butter each.
Tip: only add salt to the corn on the cob at the end, otherwise the kernels will become hard.