Preheat oven to 350°. In a large bowl, beat butter and sugars until crumbly. Beat in yogurt, oil and vanilla. In another bowl, whisk flour, baking powder, baking soda and salt; gradually beat into sugar mixture.
Shape into 1-in. balls; place 2 in. apart on ungreased baking sheets. Flatten with bottom of a glass dipped in flour. Bake 7-9 minutes or until edges are light brown. Cool on pans 2 minutes. Remove to wire racks to cool completely.
In a microwave, melt caramels with whiskey; stir until smooth. Spread over cookies. Drizzle with chocolate; sprinkle with salt if desired. Let stand until set. Store in an airtight container. Yield: 4 dozen.