Begin by taking a small mixing bowl and using a fork to mash the ripe avocado until smooth but still creamy. Season the avocado with salt, freshly cracked pepper, garlic powder, and crushed red pepper flakes. Mix well until all the ingredients are fully incorporated.
Take each slice of sourdough bread and evenly spread the seasoned mashed avocado on one side of each slice. Be generous with the avocado, ensuring a good coverage.
On the unspread side of one slice, pile on the shredded sharp cheddar cheese, creating a thick layer that will melt beautifully during cooking.
Carefully place the second slice of bread on top of the cheese, avocado side facing downward, forming a delectable sandwich.
Heat a skillet over medium heat and add the unsalted butter. Allow it to melt until it starts to shimmer.
Once the butter is hot and sizzling, gently place the sandwich into the skillet. Let it cook for about 3-4 minutes or until the bottom is a delightful golden brown and you can see the cheese beginning to melt.
With a spatula, carefully flip the sandwich over. If preferred, add another small pat of butter to the pan for an extra crispy finish. Continue cooking for an additional 3-4 minutes until the other side is golden as well and the cheese is slathered with melty goodness.
Once both sides are cooked to perfection, remove the sandwich from the skillet and let it rest for a minute. This helps the cheese set a bit, making it easier to cut.
For a burst of freshness, garnish your sandwich with a few delicate leaves of fresh basil if you wish, enhancing both flavor and presentation.
Notes
Serve on a rustic wooden board with a side of cherry tomatoes or a small salad.