Add all the ingredients, except the cornmeal, to a large pot and bring to a boil.
Add the cornmeal and stir with a wooden spoon until combined.
Spoon the mixture into a large bowl and form into a ball.
Place the polenta on a parchment-lined baking sheet. Spread out to the edges and smooth out the top. Brush with some olive oil and cut into rectangles.
Transfer to a larger baking sheet along with the parchment paper, leaving a space between each piece. Bake in the oven for 7 minutes, flip and bake for another 7 minutes.