Preheat the oven to 170 C / Gas 3. Grease a muffin tin or line with paper cases.
Mix the flour, salt, bicarb, baking powder, pepper and spices in a mixing bowl.
Beat the eggs and oil in a separate bowl. Add the butter and mix to combine. Add the milk, cheese, bacon and onion, and mix to combine.
Fold the wet mix into the dry mix. If the result is too wet and liquid, add flour, 1 tablespoon at a time. If it is too dry, add milk, 1 tablespoon at a time. Fill the prepared muffin to three-quarters full.
Bake in a preheated oven until golden and firm to the touch, about 20 to 25 minutes.