Take rice flour in the mixing bowl.
Grind fried gram dal in a mixer to a fine powder. Add it to rice flour.
Then add whole pepper and curry leaves in the mixer jar and grind it to a coarse mixture, set aside.
Soak chana dal for 10mins.
Now to the mixing bowl add chana dal and pepper mixture with salt and butter. Mix well.
Now add water little by little to form a smooth dough. The dough should not be too tight.
Take a lemon sized ball, I used 1 tablespoon measure to get all the balls of even size.
Make few balls, then take a plasic sheet grease it with oil. Keep a ball, place another plastic sheet over it then press it with a flat surfaced bowl.
Prick with fork to avoid puffing up. Carefully remove it from the plastic sheet. Flatten as thin as possible only then you will get crisp thattais.
Heat oil, carefully add 2-3 thattais at a time, deep fry till golden brown. This will take time to cook at least 3mins for each batch so fry patiently in low medium flame.
Then drain in tissue paper.
Cool down and store Pepper Thattai in an airtight container.