You can use SLOW CRAFTED jar for just about anything, from your daily juice, smoothie or iced coffee, to fresh homemade pickles, homemade jam, etc. Mix the milk and flour in the jar to a batter, then add the egg and salt and shake.
Let it rest for about two hours. Then fry in a pancake iron. If you don't have one, use a regular frying pan and try to make smaller pancakes.