For Chocolate Glaze: heat the heavy cream on the stove top or in a microwave-safe glass bowl/cup. Cream should be steaming hot but not boiling. Add the chocolate chips and allow the chips to sit for a few minutes, melting. Then, using a spoon, stir the chocolate and cream together until smooth.
If not all of the chocolate chips melt, heat the glaze in microwave at 10-second intervals, stirring after each time. If glaze is too thick, add HOT heavy cream. Do not thin out the glaze with cold cream as this will cause the chocolate to seize! Allow the glaze to cool for a few minutes if it's too hot, then pour over your cake, pouring from the center and spreading to the edges with a spatula. Alternatively, transfer the glaze into a pastry bag and drizzle down sides first, then fill center.
For Whipped Chocolate Ganache:
For Chocolate Filling: heat the heavy cream on the stove top or in a microwave-safe glass bowl/cup. Cream should be steaming hot but not boiling. Add the chocolate chips and allow the chips to sit for a few minutes, melting. Using a whisk, blend the chocolate and cream together to form a thick chocolate sauce. Then place cream into the freezer/refrigerator at 5 minute intervals.
Whisk the chocolate sauce after 5 minutes, refrigerate again, then switch over to a hand mixer. Whip the chocolate cream until it thickens, cooling again if necessary until the cream holds its shape. Be careful not to overmix the mixture or the cream can separate. This cream can also be piped and will hold its shape. Once cream is ready, use it for filling a cake, tart or cookies right away, then refrigerate. It will harden in the refrigerator.