Slice the ends off of the orange and grapefruit. Place so that they are stable and gently slice along the peel just against the flesh of the fruit to cut away the white pith. Cut in half lengthwise along the segments of the citrus. Place flat and slice to create half-moon fans.

Whisk the orange juice, dijon mustard, and vinegar together rapidly. Then slowly drizzle in the olive oil while whisking a dribble at a time until fully incorporated.

Cut the avocado in half and remove the pit. Either by whacking it with the knife or gently squeezing it out. Holding the avocado half in one hand, thinly cut slices into the flesh. With a large spoon scoop out the avocados.

Season the dressing with black pepper and salt. Toss the lettuce in the dressing first and then gently fold in the citrus and avocado slices.

Taste. Season with another pinch of salt and pepper if necessary.