Sift the flour using a fine mesh. Make sure the butter is not hard. Place the butter in a bowl and start whisking it. While whisking add sugar and whisk for 2-3 minutes. Add vanilla extract and flour and mix them together using a spatula. Make it into a dough, remove to the kitchen counter and using hands lightly mix it. Now divide the dough into 3 equal parts. Keep 1st part as is. in the 2nd part add choice chips and mix. In the 3rd part add fennel seeds and mix. Now separately divide the dough into small balls and roll them on your palms.
Line a baking tray with butter paper. Place the dough balls at a distance of 2 inches. Pre heat an oven and cook the cookies at 180 for 10 mins or til the edges start browning.