Using serrated knife, cut 24 slices from the baguette (on an angle, ¼-inch thick). Save the remaining bread for another use.
Place the slices on a large baking sheet in a single layer. Brush both sides with olive oil, then sprinkle one side lightly with salt.
Bake for 5 to 10 minutes, or until crisp throughout and lightly golden (no need to flip). Set aside and let cool.
Prep Avocado Topping:
Slice avocados in half, then remove pits. Scoop pulp into a medium bowl.
Add lemon, garlic, and salt to avocado, then mash ingredients together.
Assemble Crostini:
Divide mashed avocado evenly between crostini, then top each toast with 3 tomato slices.
Sprinkle each crostini with ¼ teaspoon everything bagel seasoning.
Serve immediately. Enjoy!
Notes
I recommend using Haas avocados for this recipe, which have the best flavor. To tell if your avocados are ripe, give them a gentle squeeze (they should have a little give). If the stem is still attached, it should easily peel it off, and if ripe, the avocado should be light green underneath. Check out the info before this recipe card for tons of helpful tips, recipe variations (more topping ideas), serving suggestions, and more!