Heat a large nonstick skillet over medium-low heat.
Brush grapeseed oil on 1 side of each bread slice. This will be the pan-contact side. Lay out all 4 bread slices, oil side down, on foil or parchment paper (as a work surface).
Spread 1 tablespoon peanut butter evenly onto each of 2 bread slices. Evenly distribute banana over the peanut buttered bread. Shingle mango evenly over banana. Scatter jalapeño over mango. Sprinkle evenly with cheese and salt. Close the sandwiches. Press gently to adhere all the ingredients.
Griddle the sandwiches for 4 to 6 minutes on each side, pressing gently to ensure that all the surface area of the bread is in contact with the pan. Be patient, and let it cook without peeking (you’ll get a more even toast that way).
Combine powdered sugar and red pepper. Cut sandwiches in half, and dust with powdered sugar mixture.
This recipe was adapted from the website, MyRecipes.