Preheat the oven to 350. Place your pie crust into your pie plate and pinch the edges for decoration.
In a small bowl mix together the sugar, flour and salt with a whisk to remove any possible lumps.
In a medium bowl, using a whisk (you can use the same one), whisk the three eggs until they are a homogenous color or till you would say they are well beaten. Then add the melted butter and milk. If the butter is still hot from melting add it slowly while you stir everything else otherwise, your butter will cook your eggs - ew. Add the vinegar and stir it into the other ingredients.
Pour your small bowl content (sugar mix) into your medium bowl and mix together well with a large wooden spoon. Mix until is is thick and smooth.
Pour this mixture into your prepared pie crust and bake on the bottom rack of your oven for 30 minutes. Half way through baking, turn the pie half way around to even brown the top. The pie is done with the pie is a little puffy and wiggles only a little when you gently shake the pan. In my oven, this was about 35 minutes, in your oven, it could take 45. Start checking at 30 minutes.
Cool the pie well before serving. you want it to be room temp or even chilled in the fridge.