Melt the butter in a small skillet over medium heat. While the butter is melting, crack two eggs in a small bowl and beat them with salt and pepper.
Pour the eggs into the pan and cook, stirring continuously with a rubber spatula, making sure to scrape the bottom of the pan. Transfer the cooked eggs to a clean bowl.
Toast the brioche bun in a 350°F (177°C) oven or in a toaster oven if your bun fits.
When the bread has toasted, place the cheese on one half of the bun and top it with the scrambled eggs, spinach, and tomato slices. Spread the mashed avocado over the other half of the bun.
Cut in half and enjoy immediately.
Notes
To mash an avocado with a fork, cut an avocado in half lengthwise. Twist to separate the two halves. With a sharp knife, stick the seed with the blade and lift out the seed. Scoop the meat from the skin of one-half of the avocado with a tablespoon and place it on a plate. Mash with a fork.Expert Tips
Read through the entire recipe before beginning. This easy breakfast sandwich recipe comes together quickly. Be sure to read through the recipe, review the ingredient notes, and gather your ingredients before starting.
Pay attention to the layers. Placing the cheese on the bun and then adding the warm eggs helps to melt the cheese which helps the eggs stay put. The mashed avocado also helps hold the tomatoes in place.
To slice the sandwich perfectly, tightly wrap the finished sandwich in butcher paper and slice it in half with a serrated knife.
For a buttery crunch, pan-fry both halves of the bread with some butter instead of toasting it.