Just back from a week in Budapest - we had an amazing time. Beautiful city, lots to see and do, weather was quite decent, very reasonably priced flights and accommodations, several kosher restaurants to choose from (3 meat, 4 dairy and all budget friendly) and all quite good and very reasonably priced (cheaper tabs than back home in Brooklyn for comparable meals and not just because the US Dollar is fairly strong right now), several places to prepay for Shabbos meals (again, excellent food and affordable), an Orthodox shul, and the Jewish area is a few minutes walk from all of the major attractions and transportation options. Couldn't recommend Budapest more as a great destination even in January for a 3-7 day visit.
That all said, we're already thinking about a European (or South American) destination for next January and we're looking for recommendations that check all the boxes I mentioned above (great destination to explore, decent weather even in January, reasonable prices for flights, airbnb, and several kosher food choices at affordable prices not too far from the touristy areas).
Any ideas?