Grease a pan or tray with some butter and keep aside. Also preheat oven at 180 degrees celsius (356 degrees Fahrenheit) for 15 minutes.
Making oatmeal cookie dough
Take whole wheat flour and chilled unsalted butter in a mixing bowl.
With a knife cut the butter in flour and make a bread crumb like texture in flour. You can also use your fingertips to mix the cold butter in the flour till the mixture resembles a bread crumb like texture. Alternatively a stand mixer also can be used. If the butter starts melting, then keep the mixture in the fridge for 20 to 30 minutes.
Then add the powdered sugar, cinnamon powder and vanilla essence.
Next add rolled oats or quick cooking oats and 2 tablespoons golden raisins. mix again well.
Now add 2 to 4 tablespoons chilled (cold) milk in parts.
Mix and bring the mixture together so that it binds into a dough. Do not knead.
Just add enough milk in parts to mix and bind the mixture very well. The cookie dough will be sticky.
Making oatmeal cookies
Now scoop out the dough with a tablespoon or any spoon.
Place the scooped dough on the greased tray. Keep some space of about 1.5 to 2 inches between the cookies.
Make cookies this way with the entire cookie dough. While working on the cookies, do note that the dough is sticky.
Now gently press the top of each oatmeal cookie with a spatula just to even it and make it smooth.
Place the cookie tray in the preheated oven in the center rack of an OTG. Bake the cookies at 180 degrees Celsius (356 degrees Fahrenheit) for 12 to 14 minutes or till the cookies become light golden.
Do not over bake them or make them too much golden as then oatmeal cookies will become hard. A way to test is with a spoon or fork press the top of the cookie. It should not create any impression on it.
Keep the tray outside for 2 to 3 minutes.
Then using oven mitts and a spatula remove the cookie and place them on a wired rack.
Once cooled then store oatmeal cookies in an airtight jar. Serve these chewy oatmeal cookies with milk or tea or coffee.
Oats: You could use quick cooking oats or instant oats, but then add less milk while making the cookie dough.
Flour: For a lighter texture in the cookies, use all-purpose flour. Adding a pinch of baking soda will also give a lighter texture.
Vegan options: Use vegan butter and almond milk or lite coconut milk.
Dry fruits, berries and nuts: You could use dried berries (cranberries, blueberries, black berries) or even chocolate chips or nuts like cashews, pecans, almonds, pine nuts, pistachios instead of raisins. Do not use raisins with seeds in them.
Sugar: White granulated sugar can be powdered and used in the recipe. You can even use ⅓ cup + 2 tablespoons castor sugar or ⅓ cup brown sugar or ⅓ cup maple syrup. For brown sugar you do not need to powder it.
Baking: Bake till the cookies are light golden. Do not bake for a longer time as the cookies will become dense and hard.