Step 1

Heat the cream, butter and sugar together in a small saucepan just until steamy. Do not let it come to a boil.

Step 2

Submerge the chocolate under the cream mixture and let it sit for 3 or 4 minutes. Whisk until smooth, making sure to get into the corners. Using a rubber spatula, go around the edges of the pan and bottom to make sure all of the chocolate is incorporated.

Step 3

Add the vanilla. Cover the surface with plastic wrap and set aside to cool. This can be made days ahead if desired. Refrigerate. When ready to use, bring to room temperature or microwave briefly - just until pipeable. Don't turn it into liquid.

Step 4

Line 9 jumbo muffin holes or 15 regular size with the paper liners. Set aside. Preheat the oven to 425°F.

Step 5

Sift the flour into a large bowl.

Step 6

Sift the cocoa, baking soda, baking powder and salt on top of the flour. Whisk together to mix well.

Step 7

In a very small bowl stir together the coffee or espresso and vanilla until the coffee or espresso is dissolved.

Step 8

In a third smaller bowl, whisk together the milk, canola oil, eggs, sour cream, and coffee mixture.

Step 9

Pour the liquid ingredients over the dry ingredients and stir with a spoon or fold together with a rubber spatula just until everything is mixed well. Do not over mix.

Step 10

With a #8 disher/scooper or a 1/2 cup measure, drop the batter into the paper lined muffin cups for the jumbo muffins. For the smaller ones, fill to abut 1/2" from the top of the paper.

Step 11

Top generously with the chocolate chunks.

Step 12

Bake at 425°F for exactly 6 minutes for the jumbo or 5 minutes for the regular size. Lower the temperature to 350°F and continue to bake for about 20 minutes for the jumbo or about 13 minutes or until a tester comes out clean. Don't over bake the muffins.

Step 13

Cool the muffins.

Step 14

Starting about 1/2" from the edge of a muffin, insert a paring knife slanted towards the middle of the muffin and go all the way around the muffin. Remove the wedge shaped cake and set aside intact.

Step 15

To enlarge the hole for more filling (why wouldn't you?), use a small spoon and scoop out additional cake.

Step 16

Fit a piping bag with a 1/2" tip, fill with the truffle filling and pipe into the hole almost up to the top. Alternately, spoon the filling in. Replace the wedge shape piece pushing it into the filling.