Whisk the eggs together with milk or yogurt, and salt, and leave for at least 15 minutes.
Cut bacon into 1/2 cm cubes.
Heat a large skillet on medium-high heat, and fry bacon until crispy.
Prepare the vegetables. Onion: peel, halve, and cut into medium dice. Garlic: peel, and cut into small pieces. Chili: remove the seeds, and thinly slice. Green beans: remove the ends, and cut into 5 cm pieces. Zucchini: cut into thin half-moons. Bell peppers: remove the seeds, and cut into 1/2 thin strips.
Add the onions, garlic, and chili to the skillet, reduce the heat to medium, and cook until they start to crisp.
Add hard vegetables to the skillet — green beans, and cook for several minutes.
Add the rest of the vegetables to the skillet, salt, and cook, stirring occasionally, until soft and slightly browned.
Remove everything from the skillet.
Reduce the heat to low, and melt 1 tbsp of butter (less or none if there is still a lot of fat in the pan).
Quickly rewhisk the eggs, and pour them onto the skillet.
Distribute the vegetables on top of the eggs.
Cook covered until the eggs are firm.
Notes & tips
If you have some chorizo, feel free to use it instead of bacon. Same with any vegetables you have left in the fridge.
The easiest way to peel garlic is to smash it: put a clove of garlic on a cutting board, put your chef’s knife on top of it so the blade side lays on the clove, and hit the side of the knife with your hand. Now you could peel the clove.