In a small bowl, combine the powdered sugar, granulated sugar, cinnamon and allspice. Set aside.
In a 2-qt saucepan, heat the oil over medium-high. Once hot, add the popcorn kernels, cover, and gently shake until all the popcorn kernels have popped. Dump into a large bowl and set aside.
In a small saucepan, add the butter and vanilla almond bark and heat over low until melted, stirring frequently. Pour into the large bowl with the popcorn and very gently fold with a spatula until the popcorn is thoroughly coated, being careful not to break the popcorn too much. Once coated, sprinkle with the spiced sugar mixture and continue to fold until all the popcorn is coated. Serve immediately, or store in an airtight container for up to three days.