In another bowl, whisk together the egg yolks, ¼ cup warm milk, and melted butter.
Cover the bowl with cling wrap and let the batter rise for about 1 hour until it doubles in volume.
Brush with oil and pour ½ cup of batter mixture into the preheated waffle maker.
Cook until crispy and golden brown. Set aside and toast the waffles before assembling.
Lay one piece of toasted waffle on serving dish then spread the avocado filling on top.
Arrange slices of grilled chicken, tomatoes, and onions on top, then sprinkle chili flakes before serving.
YIELD: 6-8 servings