For cupcakes, whisk together flour, sugar, cocoa, soda, and salt in a large mixing bowl.
Add oil, water, and vinegar. Whisk till smooth. Fold in chocolate chips.
Fill paper lined muffin cups about 2/3 full. Bake at 375° for about 18-20 minutes.
Let cool in pans for five minutes, then remove to cooling racks.
Cool completely, and pipe on the chocolate frosting. Sprinkle with mini chocolate chips if desired.
Chocolate Frosting
Combine butter and cocoa in a large bowl. Beat with an electric mixer at low speed until blended, then on medium speed for another 2 minutes, or until smooth and creamy.
Add salt, powdered sugar, vanilla, and 3 tablespoons of the cream. Beat for another 2-3 minutes at medium-high speed until fluffy, scraping the sides of the bowl a few times. If it's too stiff, you can add more cream.