Not in all recipes; for most baking recipes substituting plain flour for cornflour will not work, since cornflour has no gluten (which is what makes dough springy) and it requires far more hydration. Adding some cornflour to the flour in baking will result in lighter baked goods, but only until the total flour is 5% cornflour; after that the baked good gets progressively more dense and inedible. Cornflour is useful for thickening custards, which plain flour is not so good at. But you cannot bake normally with cornflour. Both cornflour and wheat flour have a similar calorie content, wheatflour is lower in the glycemic load (GL) index compared to cornflour, and whereas cornflour is considered "highly inflammitory" (i.e likely to cause a reaction), wheatflour is only considered "inflammitory."
Yes, you can use plain flour instead of cornflour in lemon meringue filling, but the texture may differ slightly. Cornflour helps achieve a smoother, more delicate filling, while plain flour may result in a thicker and slightly less silky consistency. If using plain flour, be sure to cook it thoroughly to eliminate any raw taste. Adjust the quantity as needed, as plain flour may require slightly more than cornflour.
No. cornflour 'hardens' the mixture so it will keep its shape, normal flour doesn't do that.
The only alternative to cornflour I know is to mix equal parts of softened butter and plain flour to form a paste and use the paste instead of cornflour.
To substitute cornflour for plain flour, use about one tablespoon of cornflour for every tablespoon of plain flour. However, since cornflour is a finer starch, it may require slightly less depending on the recipe and desired texture. It's often best to start with a smaller amount and adjust as necessary.
If I'm not mistaken cornflour is called corn starch in the States, in which case I would say: go for it. The difference will be that you will probably need less of it because it is a potent thickener.
You can use plain flour with a teaspoon of baking powder.
Yes you can, I use whatever flour I have to hand.
No, because the shortbread will rise. You can use plain flour or rice flour instead though. it would be really nice.
Yes, assuming that by "plain flour" you mean all-purpose flour. Because all three sound like the exact same thing.
I'd use regular flour.
Yes, it generally won't matter.
Hot cross buns should be made using strong bread flour.Cornflour would not work as the main ingredient.The cross is usually plain flour made into a paste with water, cornflour could be substituted to make the cross.