The Liverpool striker netted twice in an away success over Italy last week, and repeated the trick in Esbjerg as the Young Lions ran out comprehensive winners.
Solanke got off the mark with a clever header shortly before the break, and then added his second two minutes into the second half with an impudent back-heeled finish.
Meanwhile, Andy Robertson captained Scotland to a dramatic 3-2 victory against Israel at Hampden Park, which sealed Alex McLeish’s team’s promotion from UEFA Nations League Group C1.
In Milton Keynes, Roberto Firmino played the first half as Brazil defeated Cameroon 1-0 in a friendly.