First, place your muffin tin on a larger rimmed baking sheet. Add 1 teaspoon of oil into each hole of the muffin tin.
Preheat the oven to 430 degrees F. Add the muffin tin to the oven and allow it to heat as the oven preheats.
In a bowl, combine the cornstarch and eggs using a whisk until no lumps remain. Slowly whisk in the milk and salt. Whisk until fully combined.
Pour your batter into a liquid measuring cup so that it is easy to pour.
Once the oven has come to temperature, very carefully remove the baking sheet from the oven. Working quickly but cautiously, pour enough batter to fill ½-¾ of each hole. Place the baking sheet back into the oven and set a timer for 15 minutes.
Do not open the oven to check, as this will deflate them! After 15 minutes, use your oven light to check the browning. If the puddings are browned and golden, remove them. If not, keep them in the oven for up to 5 more minutes, checking through the oven window frequently.
Remove from the oven. Consume while hot. Serve with your favorite gravy for dipping.