Take a bowl and add the butter, beat it till it turns creamy. Then add the sugar and beat it for another 2 minutes. Next, put in the egg and peanut butter and mix well.
In a separate bowl, whisk the dry ingredients, flour, baking soda, baking powder and salt together. Then add these dry ingredients into the sugar and butter mixture. Wrap this dough in a plastic and refrigerate it for a minimum of 3 hours.
Preheat the oven to 190°C.
Make the dough into shapes of 1 and 1/4 inch balls. Place these dough balls about 3 inches apart on a cookie sheet that has not been greased yet. Flatten these dough balls and make a crisscross pattern with a fork.
Bake these biscuits till they turn light brown in colour, bake them for about 9-10 minutes.
Once cooked, let these biscuits cool in their baking sheets for a minute. Then transfer them to a rack and let them cool down completely.
Serve warm or you can also store them in an airtight container which could last upto 4-5 days.