Combine all ingredients and bake at 350º for 10–12 minutes.
Most home bakers fail with oatmeal cookies by skipping the hydration step for the rolled oats, which leads to dry and crumbly edges. Dissolving the baking soda in boiling water before mixing helps distribute the leavening evenly throughout the dense dough. When altering the dry ingredients, substituting pastry flour requires a higher volume than standard all-purpose flour; use 2.5 cups of pastry flour to maintain proper structural integrity against the butter and brown sugar.
Freezing and Make-Ahead Strategies
Raw drop dough freezes exceptionally well on a parchment-lined sheet pan at zero degrees Fahrenheit for up to three months. Transfer the frozen portions directly to a sealed container once solid, then bake them straight from the freezer by adding two minutes to the standard ten to twelve minute oven time at 350 degrees. Baked cookies also freeze reliably for one month when wrapped tightly in plastic and foil to prevent freezer burn. Refresh thawed baked cookies in a 300 degree oven for three minutes to restore crispness.
Scaling Quantities
Adjusting this formula up or down requires precise measurement of the butter and sugars to avoid spreading issues on the baking sheet. Doubling the batch necessitates dividing the dough into smaller mixing bowls to ensure the flour incorporates fully without overworking the gluten.