Peel the sweet potatoes and cut them into thin matchsticks (julienne-style). Aim for uniform pieces so they cook evenly

Wash and rinse with cold tap water to remove excess starches, and then pat dry

Clean the shrimp by deveining them, then using a pair of kitchen shears, snip off the rostrum and telson (the pointy parts on the head and tail), and trim off the legs and any long whiskers

In a bowl, combine the shrimp with chicken bouillon, salt, white pepper, and a splash of oil. Mix well and let the shrimp marinate while you prepare the batter

In a large bowl, whisk together all-purpose flour, rice flour, baking powder, chicken bouillon, turmeric powder, sugar, and salt until well combined. Crack an egg, then pour in the water and whisk until the batter is smooth

Add the sweet potato matchsticks into the batter and mix until evenly coated

Fill a wok or deep frying pan with oil, enough to cover the food for shallow to medium-deep frying. Heat the oil over medium-high heat to about 350F. You can test it by dropping a bit of batter in; it should sizzle immediately and float

Scoop a small portion of the sweet potato batter mixture into a large spoon or ladle and press a shrimp on top of the fritter. Add a small amount of the wet batter on top of the shrimp, using a different spoon to help it stick. Then gently lower the fritter into the hot oil

Fry each piece until golden and crispy, about 5-7 minutes or until sweet potato is crispy and cooked through

Remove and drain on a wire rack or paper towel-lined plate to cool

Serve the hot banh tom with fresh lettuce and a side of nuoc cham for dipping. To eat, wrap a fritter in lettuce, dip in nuoc cham, and enjoy!