Uzbeki Spy Hat (or Wizard Hat)

Step 2 Hat base

Cut a right triangle from the interfacing, by folding one corner to meet the opposite side, and cutting along the fold. Fold the resulting triangle in half and stitch from the point downwards to form a cone. Put the cone on your head. It should come down somewhere between forehead and nose level; trim it so it doesn't come down much below where it sits on your head, and you can see properly.

Lay the cone on your fabric, with the seam next to one edge, and cut around the bottom leaving about an inch of seam allowance. Roll the interfacing cone over towards the adjacent side of the fabric to cut the other half. Stitch a cone of this as well.