In a 10-inch skillet, cook cactus pieces and onion in the butter until the onion
is tender but not brown.
In a bowl, beat the eggs, milk, salt and pepper with a fork.
Pour the egg mixture over the cactus pieces and onion in the skillet. Cook without
stirring over low heat until the eggs start to set on the bottom and sides of the
skillet. Lift and fold the eggs with a spatula so that the uncooked part runs to
the bottom of the skillet. Continue lifting and folding about 5 minutes more or
until the eggs are set and cooked through but still glossy and moist.