In all formulas, it is essential that all ingredients be scaled/measured as accurately as possible and that they be at room temperature. Refrigerated items can be safely left out at room temperature for up to 2 hours to come to temperature.
Measure ingredients, prepare pans and being preheating oven before beginning mixing.
Creaming Method with Oil
Stir together flour and other dry ingredients, excluding salt; set aside.
In a small bowl, whisk together the flaxseed or commercial egg replacer and water; if using yogurt, leave aside; if using eggs, break into small bowl and whisk with a fork just to break yolks, set aside.
With a paddle attachment, beat together fat, sugars and salt in a large mixing bowl at medium-high speed until lighter in color and finer in texture, about 4-8 minutes; taste the mixture for doneness – it should be just a mite grainy and the sugar should crunch only slightly. If melted chocolate is being used, it may be added during this stage.
Reduce mixer speed to low and add any liquid flavorings (extracts). With mixer running, slowly add flax/replacer mixture/yogurt/eggs. Mix until just combined. Stop mixer and scrape down bowl.
With mixer on low speed, add flour mixture in three batches, waiting until each is just combined before adding the next. Scrape bowl in between additions.
If using, stir in mix-ins in one or two batches, according to recipe.
Chill, if necessary, portion, bake and cool.