Preheat oven to 400°F. Place popover pan or muffin tray inside the oven.
On a stovetop or in a microwave, begin by heating up your milk and melting your butter. Set aside until slightly cooled.
In a large bowl, whisk together the starter, eggs, flour and salt.
Whisk in your milk and butter until there are no longer any visible clumps.
Remove popover pan from oven and begin to fill each well until it is slightly underfilled.
Move tray into the oven and bake for 40 minutes.
Serve hot with your favourite butters and jams.