For Soft Ganache: Heat cream to boiling. Remove from heat, and pour over white chocolate in bowl. Let stand 5 min. Blend with immersion blender until smooth. Stir in vanilla. Refrigerate several hours or overnight. When ready to use, whip until soft peaks form. Spoon into pastry bag fitted with #6 French star tip.
For Cake Donuts: Combine first 6 ingredients in mixing bowl. Whisk buttermilk and butter in separate bowl, then mix in eggs and vanilla until blended. Add wet ingredients to dry ingredients; mix gently until almost combined. Carefully stir in 2-1/2 oz. cookie pieces. Let dough stand at room temperature 15 min. (If dough is very soft, refrigerate 15 min.)
Roll dough out on lightly floured surface to 1/2-inch thickness. Use 3-inch round cutter to cut out 15 donuts. Use 3/4-inch round cutter to cut and remove center of each donut.
Fry donuts and donut holes in 350°F oil until golden brown. Drain; cool completely. Glaze and finish each donut when ready to serve.
For each donut: When ready to serve, glaze 1 donut and hole with 3/4 oz. vanilla fondant icing. Pipe 1 oz. Soft Ganache into center of donut; top with glazed donut hole. Sprinkle with 1/4 oz. of the remaining cookie pieces, pressing into ganache. Drizzle with 1 oz. caramel sauce.