Step #1 To toast: Lay pappadum wafers (see notes) slightly apart on a baking sheet.
Step #2 Broil 4 to 6 inches from heat until they begin to blister or buckle, 20 to 25 seconds (watch closely--they scorch easily).
Step #3 Turn wafers over & broil again until surface is blistered, 8 to 12 seconds longer.
Step #4 Transfer toasted wafers to a rack.
Step #5 To fry: Pour about 1 inch of vegetable oil into a 10- to 12-inch frying pan over medium-high heat; when oil reaches 375º on a thermometer, adjust heat to maintain temperature.
Step #6 Lay 1 pappadum wafer in hot oil; when it puffs up (almost instantly), push other side into oil, & cook this until puffed & crisp (it doesn't need to brown), turn it over, 2 to 3 seconds.