Cut avocado in half, remove the seed, and scoop flesh into a small bowl. Add lime juice, salt to taste and several turns of freshly ground black pepper. Using a fork, mash mixture until all ingredients are well combined. Consistency should be somewhat chunky.

Add bacon slices to a cold skillet and cook over low heat. Cook bacon, flipping occasionally, until crispy. This method takes a little longer, but will ensure that your bacon doesn’t curl up. Transfer bacon to a paper towel-lined plate to drain off excess grease.

Increase heat under the skillet to medium. After a few moments lay sourdough slices down in the bacon grease. Cook bread until golden brown on one side then flip. Once the second side is lightly golden, transfer bread to the paper towel-lined plate with the bacon.

Spoon some of the avocado spread on the sides of the bread that are lightly golden. Arrange frisée, sliced tomato and cooked bacon on top of one slice of bread. Close the sandwich, then cut in half.