Bring the stock to boil in an oven ready casserole pot.
Then slowly add in the polenta whisking all the while till it thickens. Reduce the heat to low and stir for a few minutes with a wooden spoon. Then cover and stir every 8 or so mins until the polenta is cooked. The whole cooking process takes about 45 mins. The polenta is cooked when it is very thick and falls away from the side of the pan. When the polenta is cooked, stir in the cheese before switching off the heat.
Preheat the oven to fan-assisted 160C / 180C / 350F / gas 4.
Add bacon to a frying pan and cook until done. Mix in the spring onion, sweetcorn and tomatoes and fry for a min. Stir in the chipotle paste and switch off the heat.
Top the warm cooked polenta with the refried beans, then the chipotle bacon mix and bake for 15-20 mins in the preheated oven.