Toast the bread: Heat a skillet over medium. Add a little olive oil or butter and toast your bread until golden and crisp on both sides. You can also use a toaster and skip the pan if you prefer.
Mash the avocado: In a small bowl, mash the avocado with lemon juice, salt, and pepper.
If you like heat, add red pepper flakes. Keep it a bit chunky for texture.
Warm the cheese (optional): If using cheese, place slices on one piece of the hot toast. Cover the pan for 30–60 seconds to help it melt, or just layer it on and let the residual heat do the work.
Prep the veggies: Slice the tomato, onion, and cucumber thinly.
Pat tomato slices dry with a paper towel to prevent sogginess.
Spread the base: Spread hummus or pesto on one slice of bread. Spread the mashed avocado on the other slice.
Layer the vegetables: Add spinach or arugula first, then tomato, cucumber, and red onion. Season with a pinch of salt and pepper.
A sprinkle of everything bagel seasoning is great here.
Add optional protein: If using an egg or plant-based sausage, cook it in the same skillet while you slice the veggies. Layer it on top of the vegetables.
Assemble: Close the sandwich gently, press slightly to help everything settle, and slice in half if you like.
Serve: Enjoy right away while the bread is warm and the veggies taste crisp and fresh.