Dissolve the remaining 1 teaspoon of yeast in 1/4 cup of the water. Put 1 cup of the cornmeal in a large heatproof bowl. Bring the remaining 1/4 cup of water to a boil, then stir it into the cornmeal and let cool. Stir in the salt, both yeast mixtures and the remaining 1 1/3 cups of flour to make a soft dough. Transfer to a floured surface and knead until smooth and elastic, about 15 minutes. Knead in the pumpkin seeds. Return the dough to the bowl, cover with plastic wrap and let rise for 1 hour.