Preheat the oven to 180C/350F/Fan 160C/Gas Mark 4. Grease 6 holes of a muffin tin and line the bases with circles of baking paper (or line with paper muffin cases). Grill or fry the bacon until crisp, finely chop and set aside.
Place the polenta in a bowl and sift in the flour, baking powder, bicarbonate of soda and cayenne pepper. Season with salt and freshly ground pepper and stir in the Cheddar and chopped bacon.
In a separate bowl beat together the yogurt, oil and eggs. Add the dry ingredients and stir lightly and quickly to mix. The mixture should still be a bit lumpy, if over mixed the muffins will be heavier.
Divide the mixture between the muffin tins and bake for 20-25 mins until golden and just firm to the touch. Cool in the tin for 5 mins before turning out. Serve warm or cold.
Notes
For vegetarians replace the bacon with 50g cooked and chopped mushrooms or 75g wilted spinach, squeezed of excess liquid and finely chopped. Also ensure the cheese you use is suitable for vegetarians.