The 19-year-old moved from League One side Charlton Athletic to Goodison Park in January and has started the club's last two Premier League matches.
Lookman also scored in the 4-0 win over Manchester City on January 15 just two minutes after coming on as a substitute for his debut.
"I'm not surprised [about Lookman's initial success] because I am watching him in training every day," the Dutch coach told Everton's official website. "He now knows what intensity he is up against and the quality of the players around him.
"It's a big challenge for Ademola but he is doing well. He is the future of the club. He's a big, big talent who is working hard to improve, like everybody.
"Ademola is a good example in that if you are good enough you will play and there are others here like him who will get their chance if they keep working hard. It's very encouraging. The club has some good, young boys coming through and as a team that's exactly what we want."
Everton's players are currently in Dubai for a training camp and will not be in action again until February 25, when they host Sunderland in the Premier League.