LONDON, ENGLAND - APRIL 24: Yannick Bolasie of Crystal Palace celebrates as he score their first goal during The Emirates FA Cup semi final match between Watford and Crystal Palace at Wembley Stadium on April 24, 2016 in London, England. (Photo by Richard Heathcote/Getty Images)

Yannick Bolasie has become Everton's top transfer target, but the Toffees have had a bid rejected.

Everton boss Ronald Koeman has been on the lookout to strengthen his squad since he took over in June, and believes Bolasie is the player that can improve their attacking stocks.

Crystal Palace have rejected the formal £18m bid for the 27-year-old, with the club holding out for a fee closer to their valuation of £30m.

The Democratic Republic of Congo forward has impressed with Palace since they were promoted in 2013, with his speed and trickery on the ball a nightmare for defenders.

Bolasie has scored five times for Palace in the league and has made 79 appearances, but this year faces some competition on the wings.

Alan Pardew recently shelled out a club record transfer fee for forward Andros Townsend, which leaves the door open for a Bolasie exit should Palace choose Townsend instead.