With yarn held double, loosely cast on 46 sts and work twisted ribbing in the round for 6 cm.
Knit 1 round increasing 44 sts: k1, *kfb (= knit next st through front and back loops)*, repeat *–*, k1 = 90 sts.
Work stockinette st in the round.
When the piece measures 16 cm, place 5 markers: 1st marker at the beginning of round and the rest after every 18 sts.
Continue in stockinette st and decrease 1 st on both sides of each marker: *work to last 2 sts before marker, skp (= slip 1 knitwise, k1, pass slipped st over), slip marker, k2tog*, repeat *–* 4 more times. 10 sts decreased. Repeat the decreases on every 3rd round 7 more times. 10 sts remaining.
Break yarn, pull it through the sts and securely weave in.
Steam the beret lightly.
Make a small pompom and attach it to the hat.