2tablespoonsunsalted butter(28 grams or 1 ounce), divided (if using salted, omit the salt)
2tablespoonscoconut flour(14 grams or ½ ounce), divided
½teaspoonDiamond Crystal kosher saltdivided (or just a pinch of fine salt)
½teaspoonbaking powder,divided (gluten free if needed)
Olive oil sprayfor toasting the breads
½cupshredded sharp cheddar cheese,divided
Make the tuna salad:
In a small mixing bowl break up the tuna with a fork. Mix in the celery. Add the mayonnaise, mustard, black pepper, dried parsley, onion powder and garlic powder. Stir to combine. Set aside.
Make the breads:
In a small microwave-safe bowl (mine measures 3 inches on the bottom and 3.5 inches at the top), melt 1 tablespoon unsalted butter in the microwave.
Allow the melted butter to slightly cool, then mix in 1 egg and 1 tablespoon coconut flour. Mix thoroughly, until very smooth. Mix in the kosher salt and baking powder.
Microwave the mixture on high for 90 seconds. Be careful when removing the bowl from the microwave. It will be hot.
Allow the bread to cool for a minute or so. Gently, with a paring knife, loosen the bread edges and remove from the bowl onto a plate. Slice the bread crosswise into two slices.
Repeat steps 1-4 to make a second bread.
To toast the bread slices, heat a large nonstick skillet over medium-low (not higher) heat. Spray it with olive oil. Add the four bread slices. Cook, gently pressing on them with a spatula to ensure even toasting, until golden, about 3 minutes per side.
Assemble and broil the tuna melts:
Preheat the broiler on high (450 degrees F) and set the rack 4 inches from the heat source.
Place the four slices of toasted 90-second bread on a broiler-safe pan (I use a stainless steel skillet). Divide the tuna salad equally between the four slices. Top each slice with a quarter of the shredded cheese.
Place the pan under the broiler and broil just until the cheese has melted, about 1 minute. Serve immediately.
Coconut flour is extremely absorbent, so it's best to measure it by weight and not by volume, as even a slight variation could render your bread dry.