Beat the egg in a large mixing bowl; add the starter, milk, and salt. Whisk to combine thoroughly.

Heat a large non-stick skillet over medium heat, and grease the pan with about 1/2 tsp. butter. When the butter is hot and bubbly, pour about 1/2 cup of crêpe batter into the pan, and tilt the pan to spread to a large thin round.

Cook the crêpe over medium heat until the wet batter looks dry on the top, and the underside is lightly browned. Flip, and cook for a moment longer until the other side is browned.

Slide the finished crêpe out onto a plate, and repeat with the remaining batter until all of the crêpes are done.

Serve immediately with desired toppings.