Working in batches, add the corn kernels to a blender or food processor and puree until smooth.
In the bowl of an electric mixer, cream the butter and sugar until pale. Add the egg, salt, and baking powder. Mix to incorporate. Add the flour and pureed corn and mix until blended and forms a loose smooth dough.
Put a corn husk lengthwise in front of you with the wide side closest to you. Spread 3 tablespoons of the dough all over the bottom half (wide side) of the corn husk, leaving about a 1-inch-wide border on the left and right sides. Pick up the 2 long sides of the corn husk and bring them together. Roll both sides of the corn husks in the same direction over the filling.
Repeat with remaining corn husks and dough. Arrange the tamales, seam side down, in a steamer and add 1/2-inch of water. Cover with a tight fitting lid, bring to a simmer and steam for 1 hour, adding additional water, as needed to maintain 1/2-inch of water in the pan. Remove the tamales from the steamer to a serving platter and serve.