Step #1 Stack tortillas, & heat in a 375° oven until hot, seal in foil wrap, 10 mins.
Step #2 In a 12-inch nonstick frying pan over med-heat/flame, melt butter.
Step #3 Break eggs into pan, slightly apart; cover & cook just until whites are almost firm & yolks are still soft, about 3 mins.
Step #4 Meanwhile, spread 1/2 c lettuce on each plate.
Step #5 Lay tortillas on lettuce & spoon beans over tortillas.
Step #6 With a wide spatula, transfer an egg to each serving.
Step #7 Spoon tomato salsa around one side of eggs, green around the other side.
Step #8 Sprinkle top with cheddar cheese, then cotija.
Step #9 Garnish as desired with avocado, sour cream, jalapeño chilies, & lime wedges; add salt to taste.
Step #10 Enclose remaining tortillas in a linen napkin to keep warm, & serve alongside.
Step #11 Bacon black beans: In a 10- to 12-inch frying pan over medium-high heat, stir 4 oz.
Step #12 sliced bacon (4 slices) until crisp & brown, 5 to 7 mins.
Step #13 With a slotted spoon, transfer to paper towels to drain.
Step #14 Spoon all but 2 tbsps fat from pan (save for huevos, preceding, if desired, or discard) & add 2 minced or pressed garlic cloves & 1 c sliced onion.
Step #15 Stir often over high heat until onion is limp, about 3 mins.
Step #16 Meanwhile, rinse & drain 2 cans (15 oz.
Step #17 each) black beans; add to pan along with 1 c fat-skimmed chicken broth.
Step #18 Stir often until most of the liquid is evaporated, 5 to 7 mins.
Step #19 Stir bacon into beans.
Step #20 If beans have gotten too dry, thin with a little more broth.