Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 10-inch Bundt or tube pan.

Whisk flour, baking soda, salt, allspice, cinnamon, and nutmeg together in a medium bowl. Set aside.

Beat oil, eggs, and sugar together in a large bowl at medium speed until well combined.

Add the flour mixture alternately with buttermilk, beginning and ending with the flour mixture. Beat well after each addition. Fold in prunes, pecans, and 1 1/4 teaspoons vanilla. Spread batter into the prepared pan.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 1 hour.

Poke deep holes all over the hot cake with the handle of a wooden spoon or a skewer.

To make the glaze: Combine butter, buttermilk, corn syrup, and sugar in a saucepan over medium heat. Cook, stirring occasionally, until the butter melts and the sugar dissolves. Remove from the heat and stir in 2 teaspoons vanilla.

Slowly spoon the warm glaze over the hot cake, allowing it to soak into the holes before adding more.