He was likely introduced to ice cream in France. A copy of his hand-written recipe is in the Library of Congress. When he became president, Jefferson served it at the Presidential Mansion in Washington -- the White House wasn’t built yet.
If you want to make Jefferson’s ice cream yourself, here’s the recipe.
Thomas Jefferson's Vanilla Ice Cream
makes about 4 pints (2 quarts, 1/2 gallon)
6 yolks of eggs
1/2 lb sugar (1 1/4 cups)
2 bottles (quarts) of good cream (4 pints)
1 vanilla bean
Mix the yolks and sugar together. Put the cream on a fire in a casserole, first putting in a stick of vanilla. When near boiling, take it off and pour it gently into the mixture of eggs and sugar. Stir it well. Put it on the fire again, stirring it thoroughly with a spoon to prevent it's sticking to the casserole.
When near boiling, take it off and strain it thro' a towel. Put it in the Sabottiere* then set it in ice an hour before it is to be served. Put into the ice a handful of salt. Put salt on the coverlid of the Sabotiere and cover the whole with ice. Leave it still half a quarter of an hour. Then turn the Sabottiere in the ice 10 minutes open it to loosen with a spatula the ice from the inner sides of the Sabotiere.
Shut it & replace it in the ice open it from time to time to detach the ice from the sides when well taken (prise) stir it well with the spatula. Put it in moulds, justling it well down on the knee. Then put the mould into the same bucket of ice. Leave it there to the moment of serving it. To withdraw it, immerse the mould in warm water, turning it well till it will come out and turn it into a plate.
*The Sabottiere is the inner cannister of what we now know as an ice cream maker.