To a large bowl add oats (pulse them 2-3 times in a food processor to break them a little), atta, all purpose flour, sooji, baking powder and stir. Add salt and ajwain and mix everything together.
Start adding oil, around 3.5 tablespoons and rub the oil into the flour mix with your fingers.
Hold the dough in your hands and press between your palms. If it holds shape, then oil is enough, if it crumbles then add the remaining 1/2 tablespoon of oil and mix.
Now start adding water to bring your dough together. I use my stand mixer here but you can do this by hands too.
Add water little at a time and knead to a stiff dough. I used little more than 1/2 cup water here, probably 1/2 cup + 1 tablespoons. Cover the dough with a cling sheet and rest dough for 20 minutes.
Then start rolling the dough using a rolling pin, roll somewhere between 1/6 to 1/8 inch thickness.Cut the dough vertically into strips and then diagonally to cut into diamonds, 3/4 inch inch wide. You can cut them in any shape you like.
Arrange them on a baking sheet lined with parchment paper and bake at 375 F degrees for 18-20 minutes or until crispy. Keep an eye after 15 minutes so that they don't burn. Let cool completely and then store these oats namak pare in an airtight container at room temperature.
Notes
These oats namak pare can be flavored with kasuri methi (dried fenugreek leaves), black pepper, turmeric etc.
The calories mentioned are for 350 grams of namak pare (the entire batch).