For batter, combine flour, yeast, spices, sugar, salt and bourbon and mix well. Add soda water and whisk briefly. Allow to stand in a warm spot for 2 hours. Batter should foam and be well risen.
Heat vegetable oil in a saucepan until hot.
Place grape tomatoes on the end of the skewers, dust in flour then dip in batter. Drain well.
Immerse tomato in hot oil until golden, drain on paper towel and roll in remaining Cajun spices.