Heat oil in a large, deep pot over medium-high heat. Add tempeh, in one piece, and sear on one side for about 1 minute, or until lightly colored. Turn and sear other side for 1 minute. Remove from pan and cool slightly. Reduce heat to medium and add garlic; stir briskly for about 10 seconds. Stir in chopped kale until it wilts into mixture. Add roasted pepper purée and stir well. Cover, reduce heat to medium-low, and cook, stirring occasionally, until tender, about 3 minutes. (Note that unlike spinach, kale will retain some chewiness, even when cooked.) Season with salt to taste.