In a blender or food processor, combine the roasted pepper, garlic and 1 tablespoon of the water. Process until smooth; set the coulis aside.
Heat the oven to 450 F. Lightly coat a 9-inch round cake pan with olive oil cooking spray.
In a large saucepan, combine the soy milk, remaining water, olive oil and salt. Whisk in the polenta and place over medium heat. Whisk constantly until the polenta begins to thicken. Reduce the heat to low and resume stirring with a wooden spoon. Cook, stirring frequently, until the polenta pulls away from the sides of the pan, about 15 minutes. Add the coulis and stir to combine.
Pour the mixture into the prepared cake pan and sprinkle with the cheese. Bake until firm, about 15 minutes. Let stand in the pan for 10 minutes before serving. Cut into 6 wedges and sprinkle with the thyme.