1. Reconstitute the corn husks.

2. Place 2 cups corn kernels in the bowl of a food processor, and pulse into a medium- coarse puree. Add the butter, and pulse 5 or 6 times. Add the masa, sugar, salt, and baking powder; pulse until thoroughly combined. Process until the mixture is light, fluffy, and homogenous, about 1 minute, stopping to scrape down the sides of the bowl once or twice.

3. Transfer mixture to a medium bowl, and stir in remaining 3/4 cup corn kernels until combined. Chill corn filling until ready to use.

4. Assemble 14 tamales with the corn filling, using the large husks for wrappers and ties, and reserving the smaller ones to line the steamer basket and to cover the assembled tamales.

5. Prepare the steamer, and steam the tamales. Let stand until the batter has firmed. Serve tamales with sour cream and Chopped Tomato and Serrano Salsa.