Set up a double boiler by filling a saucepan with about 3-inches of water. Bring to a simmer.
Add a large bowl on top (one that will not touch the water on the bottom) and add white chocolate chips and vegetable oil to the top bowl.
Stirring frequently, cook until melted.
Remove from heat and let stand 30 seconds.
Add mascarpone cheese and mix until smooth.
Add orange zest and vanilla; continue to mix until thoroughly combined.
Cover with plastic wrap and refrigerate for 2 hours.
Remove from fridge and let stand 3 minutes.
Line a baking sheet or plate with wax paper.
Using a teaspoon or a melon baller, scoop out the mixture and form into 1-inch balls.
Dip each ball in the melted chocolate candy coating.
Set on prepared baking sheet.
Repeat until all truffles are done.
Pour the melted white chocolate in a piping bag or in a ziploc bag with the corner cut-off, and drizzle the melted chocolate over the truffles.
Refrigerate until ready to use.