Here are 25 time-tested vintage baking tips!

1. Butter and sugar can be creamed easily when butter is hard by warming the sugar slightly.
2. Light-colored molasses can be darkened to make dark gingerbread by adding a teaspoonful of melted chocolate to each cup of molasses.
3. Cream which is hard to whip will whip quickly by adding a few drops of lemon juice.
4. Molasses can be prevented from sticking to the measuring cup if the cup is first greased with butter or lard.
5. Shortening can be measured exactly. If recipe calls for 1/3 cup, fill measuring cup two-thirds full of water, add enough shortening to bring water to top of cup, pour off water and you have exactly 1/3 cup of shortening.
6. Sour milk can be made by adding two (2) tablespoonfuls of vinegar to one (1) cup of sweet milk and then letting it stand for a few minutes. Your baking will be just as light as if real sour milk were used. Also see Handy Substitute Recipes For Baking.
7. Whipped cream substitute, delicious in flavor, can be made by adding a slice of banana to the white of an egg and beating until stiff. The banana will dissolve completely.
8. Cornstarch is sometimes used in place of eggs when recipe calls for more than you have on hand. A tablespoonful is used for each missing egg. In making custard, omit one or two eggs, and use cornstarch instead (1/2 tablespoon for each egg).
9. Custards will not curdle so readily if a tablespoon of flour mixed with sugar is added.
10. Boiled frosting will not be brittle or break when cut, if a teaspoon of vinegar is beaten into the frosting when the flavoring is added.
11. Add one tablespoonful of jam or jelly to cookie dough. It will add flavor and make the cookies stay moist longer.
12. Doughnuts will not absorb grease if a teaspoonful of vinegar is added to cold fat.
13. Fruit Cake: When baking, place a cup of water in the oven to keep enough moisture in air and prevent cake from drying out while baking. Also see Fruitcake Baking Tips.
14. Muffins: Drop a teaspoonful of peanut butter in each muffin pan, over which pour batter. This gives muffins a delightful nutty flavor. Also see 10 Tips For Baking Muffins.
15. When a recipe calls for a quantity of melted butter, take care to measure the butter after melting, not before.
16. To soften butter, fill a small china bowl, one just sufficiently large to cover the butter, with boiling water; let stand a minute or two or until thoroughly heated, then empty the water and immediately turn the hot bowl upside down over the butter. In a few minutes, the butter will be softened so it is just right.
17. When separating the yolk from the white of an egg, if you drop a portion of egg yolk into the whites, moisten a cloth with cold water, touch to the yolk and it will adhere to the cloth.
18. Never beat egg-whites in an aluminum pan, as it is sure to darken them.
19. When baking a milk pudding, place the dish in a tin of water in the oven. Then prevents the pudding from burning or boiling over.
20. When cream will not whip, add the white of an egg to your cream–chill it and it will whip.
21. To avoid lumps in batter, add a pinch of salt to the flour before it is wet.
22. How to sugar doughnuts? Shake the sugar and doughnuts together in a paper bag. The same method may be used with flour and chicken, or salt and french fried potatoes.
23. Raisins for cakes and breads will be plump and juicy if soaked in warm water before being added to the batter or dough.
24. Zip up your gingerbread and molasses cookies by adding a bit of grated orange peel to the batter.
25. If chilled ice-box cookie dough shatters when cut with long sharp knife, let stand at room temperature for 1/2 hour to soften very slightly before slicing!

Source: Tipnut.com