Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.
In a large bowl, whisk together the flour, baking powder, garlic powder, onion powder, salt, and black pepper until well combined.
In another bowl, beat the eggs and then stir in the buttermilk and melted butter until smooth.
Gradually add the wet ingredients to the dry ingredients, mixing until just combined. If using, fold in the shredded cheddar cheese.
Dip each slice of bread into the batter, ensuring both sides are coated, and place them on the prepared baking sheet.
Bake for 15-20 minutes, or until the toast is golden brown and crispy. Flip the slices halfway through baking for even crispiness.
Remove from the oven and let cool slightly. Garnish with chopped parsley before serving.