JAKARTA — While European Union leaders were in the middle of another round of Brexit talks in Salzburg this week, the European Commission was pitching a plan to boost Europe’s infrastructure links with Asia. The commission, a key EU decision-making body, estimates that Asia needs 1.3 trillion euros ($1.5 trillion) a year in infrastructure spending over the next few decades. European infrastructure upgrades will cost a projected 1.5 trillion euros between 2021 and 2030, it said. EU foreign ministers will vote on the plan ahead of a meeting of leaders of 51 countries across Asia and Europe in Brussels next month. Financing details are hazy, with the commission suggesting that it draws on existing EU funds, loans from development banks and public-private partnerships. Some analysts say the plan — titled “The European Way to Connectivity” — suggests that the EU is proposing an alternative to China’s flagship Belt and Road Initiative, an ambitious collection of road, rail and port projects in 60 countries spanning Asia, Europe and Africa.