For the butter, chop butter into cubes, place in a mixing bowl and bring to room temperature. Beat butter with a wooden spoon until soft and creamy. Fold through the remaining ingredients. Place mixture on a sheet of baking paper and roll into a log shape, about 4cm in diameter.
Wrap in plastic wrap and refrigerate until firm. Cut into about 12 slices.
For the salad, place tomatoes in a bowl along with coriander, thyme and roughly torn basil. In a mortar with a pestle, pound the garlic with a little salt until puréed. Add lime juice, then whisk in oil. Dress the tomatoes.
For the fritters, sift the rice flour, plain flour, baking powder, salt, coriander and cumin into a bowl. Add egg, lemon juice and 1/2 cup water and beat to a smooth batter. Add corn, spring onions and coriander, then stir to combine.
Heat oil in a large, non-stick frying pan over a medium to high heat. When the oil is hot, spoon a little less than ¼ cup of the fritter mixture into pan and flatten gently with the back of a spoon. Cook for 2-3 minutes each side until golden brown. Drain on absorbent paper and keep warm.
Serve the fritters with butter on top and salad on the side.