Preheat oven to 400°F. Coat large ovenproof Dutch oven or flameproof casserole with vegetable cooking spray and heat over medium-high heat. Add tempeh, onion, bell pepper and jalapeño pepper and cook, stirring often, until tempeh is browned and vegetables soften, about 10 minutes.
Add tomatoes (with juice), corn, chili powder, cumin and ground pepper. Reduce heat to medium-low and simmer, stirring occasionally, until flavors have blended, about 10 minutes. Remove from heat.
Meanwhile, make topping. In medium bowl, mix cornmeal, baking powder, milk, egg and oil just until blended.
Spoon cornmeal mixture over top of tempeh mixture. Bake until topping is lightly golden and set, 15 to 20 minutes. Serve hot.