Butter both sides of the bread slices and place bread on a sheet pan. The tuna mixture makes enough for four regular size open-faced tuna melts. Either butter four slices of bread and use all the tuna mixture OR butter two sliced of bread and save half the tuna mixture for later.
For the tuna salad mixture, in a small bowl stir together tuna, mayo, Sriracha, pickle relish, and black pepper. Add salt if needed.
With broiler on high, toast first side of the bread under the broiler, and then flip the bread over and very lightly toast the second side.
Remove sheet pan from oven. Top the lightly toasted side of the bread with the tuna mixture and shredded cheese. Leave the edges of the bread just slightly exposed, for additional toasting.
With the broiler on low, place sheet pan back into oven. Let the tuna salad mixture and cheese get thoroughly heated, nice and slow. Once cheese is melty, turn the broiler to high to blister the cheese just a bit, if desired. Take care to not let the bread burn.
Remove sheet pan from oven and drizzle Sriracha over the top of the finished melts. Garnish with fresh cilantro, if desired. Then enjoy while it’s hot!
