Start by toasting or grilling your bread. I highly recommend using sourdough, but a whole grain loaf or gluten-free bread would be great too!
While the bread is toasting, scoop out the avocado from its shell, and mash in a bowl with the lemon juice, salt, and black pepper. You can definitely use a whole avocado if you'd like, just add in more seasonings to your preference.
Once bread is toasted, spread the seasoned avocado mash onto the toast. Add whatever toppings you like... I always add hot paprika, pumpkin seeds, and chili flakes.