Preheat a countertop oven or standard oven to 400°F (200°C).
Apply the spread and fillings to the sandwich according to its type, but leave off any raw internal garnishes. If using deli meats, fluff them for best mouthfeel.
If making a simple sandwich, divide the filling between the 2 pieces of bread product. If using cheese, place it underneath the fillings (A).
If making an open-face sandwich or a hollowed long roll sandwich, place the cheese under or between the other filling ingredients.
Place the sandwich on a sizzle plate and put it in the oven.
Bake the sandwich until the filling is hot and the cheese, if any, is melted.
Remove the sandwich from the oven.
Add the raw internal garnishes (B).
Unless making an open-face sandwich, close the sandwich (C) and press gently to firm it.
If necessary, secure the sandwich closed with sandwich picks. Cut the sandwich as desired.
Place the sandwich on a plate and add any external garnishes.