I just made a batch of these with a recipe I got from my mother.
They are easy enough to make and they turned out beautifully.
They can be filled with just about anything. She used lemon curd,
which was very nice

1/2 cup brown sugar
1 cup soft butter
2 cups flour

Cream butter and sugar then add flour a half cup at a time. It
may only need 1 1/2 cups, and should be a malleable texture. Form
3/4 inch diameter balls and place in the cups of a small muffin
pan, then press a shot glass, wine bottle cork or some something
like that... I used a stone pestle into the balls to form tarts.
Bake at 350 for 20 minutes. Makes about 3 dozen tart shells.