Preheat the oven to 190 degrees C. Grease a muffin tin or line with muffin papers.
In a large bowl whisk together the flour, polenta, baking powder, bicarb soda, thyme, fennel seeds, salt, pepper and sugar. Make a well in the center and pour in the soy milk, egg, egg yolk and oil. Stir just until blended. Spoon into the prepared muffin tin, filling cups about 3/4 full.
Bake for 18 to 20 minutes in the preheated oven until the tops of the muffins spring back when lightly pressed. Cool in the pan for at least 5 minutes before removing from cups.