Slice the avocado and drizzle with lime juice to prevent browning.
Spread vegan butter on one side of each bread slice.
Heat a skillet over medium heat.
Place one slice, buttered side down, on the skillet.
Add vegan cheese, avocado slices, salt, and chili flakes.
Top with the second slice, buttered side up.
Grill 3–4 minutes until golden brown and crisp.
Flip carefully and cook the other side until the cheese melts beautifully.
Slice diagonally and serve hot with your favorite dip.