Place chocolate in microwave safe bowl
Heat for 30 seconds, stir and continue heating for 10 seconds at a time, stirring after each heating until completely melted
Set aside to cool
In a large bowl, beat together the oil, sugar and melted chocolate
Add eggs one at a time, mixing well after each addition
Add vanilla and beat well
In a small bowl, whisk together the flour, baking powder and salt
Gradually add dry mixture to wet mixture until well combined
Transfer to bowl and cover with plastic wrap
Place in refrigerator to chill several hours or overnight
Remove from refrigerator and set on counter about 20 minutes to warm up slightly
Preheat oven to 350 degrees
Line baking sheets with parchment paper or silicone mat
Place powdered sugar in medium bowl
Roll dough into balls and coat with powdered sugar
Bake for 10-12 minutes or until edges are set
Remove from oven and let set on baking sheets for 2-3 minutes
Transfer to wire cooling rack and cool completely
Store in airtight container for up to 5 days