To make sauce, combine peanut butter, galangal powder, Kecap Manis, lime juice and 2/3 cup water in a saucepan.
Simmer for 10 minutes until sauce is smooth and thick.
Meanwhile, let's make our Bakabana.
In a bowl, combine flour, cornstarch, salt. Whisk to remove any lumps.
Add club soda and mix until you have a thick, smooth batter.
Peel plantains. Slice once horizontally. Cut each half into 3 slices, so you will have a total of 12 slices.
Heat enough oil for deep frying in a deep skillet.
Dip plantain slices one at a time into the batter so that it is evenly coated on all sides.
Place in the hot oil and fry until golden brown on both sides. Remove to a paper towel to absorb excess oil.
Garnish peanut sauce with crispy fried shallots.
Serve Bakabana with peanut sauce.