Cookies and Cream Dark Chocolate Cheesecake with Ganache Top Step-by-step instructions

Before you start

Gather all the ingredients and tools before you start, since the cheesecake moves quickly from crust to filling to topping. Set the cream cheese, eggs and sour cream out to reach room temperature, which usually takes about one hour. Preheat the oven to 325°F (163°C) and place the rack in the center. Wrap the outside of the springform pan in two layers of heavy foil to keep water out during baking.

Chop about two-thirds of the chocolate sandwich cookies on the wooden cutting board, keeping the rest whole. Finely chop the dark chocolate for the ganache and grate the remaining bar for shavings later. Have the metal pitcher, the piping bag and the star tip ready so the ganache and whipped cream can go on without delay once the cheesecake has cooled.

Instructions

Crust pressed and chilled

1. 1Chop the cookies and build the crust
   Chop about two-thirds of the chocolate sandwich cookies roughly with a chef's knife into irregular pieces and crumbs on a wooden cutting board. Keep the rest whole for decorating. Mix the crumbs with the melted butter, press the mixture firmly into the base of a 9-inch springform pan, and chill while you prepare the filling.
   Look for The crumbs hold together when pinched and the base looks evenly dark and compact.
   Tip Press the crust with the flat bottom of a glass so it packs tightly and does not crumble when sliced.

The crust should look evenly dark, hold together when pinched, and feel firm when pressed with the back of a spoon. Its edges should stay in place with no loose crumbs falling away. Chill it for at least 15 minutes so it firms up before the filling goes on. If the crust feels crumbly or sandy, press it more firmly and chill again. A solid, compact base prevents cracking and keeps each slice neat when the cheesecake is cut. Do not pour the filling until the base feels cool and firm to the touch.

Filling baked and cooled

2. 2Make the cream cheese filling
   Beat the softened cream cheese and granulated sugar in a mixer until smooth and free of lumps. Add the eggs one at a time, mixing briefly after each, then stir in the sour cream and vanilla. Pour the pale filling over the chilled crust, spread it smooth, and bake at 325°F (163°C) for about 55 to 60 minutes until the edges are set and the center barely trembles.
   Look for The edges look set and the center moves only slightly when the pan is gently shaken.
   Safe temperature 160°F (71°C) internal temperature (egg dishes)
   Tip Mix on low speed so the filling does not take in extra air, which can cause cracks.
3. 3Scatter cookies and pour ganache
   Once the cheesecake has cooled, scatter the chopped cookie pieces across the top of the filling. Heat the heavy cream until steaming, pour it over the finely chopped dark chocolate, wait one minute, and stir until glossy. Pour the ganache from a metal pitcher in a thick, even stream over the surface and spread it gently to the edges.
   Look for The ganache looks smooth, glossy and pourable without streaks of cream.
   Tip Let the ganache cool for a few minutes so it thickens slightly and holds its shape on top.

After baking, the edges of the cheesecake should look set and slightly dry, while the center still moves gently when the pan is shaken. The surface should be smooth and pale with no deep cracks. Let the cheesecake cool on the counter for one hour, then refrigerate it until fully chilled.

Before you scatter the cookies and pour the ganache, check that the filling is firm and that no moisture has collected on the surface. A properly cooled filling gives the ganache a stable place to sit and keeps the layers distinct.

Ganache poured and set

4. 4Chill, decorate and slice
   Refrigerate the cheesecake until the ganache is set, at least 6 hours or overnight. Whip the cold heavy cream with confectioners' sugar to stiff peaks. Pipe rosettes in a ring around the edge, place the reserved whole cookies between them, and drizzle thin dark chocolate lines across the top. Grate the dark chocolate bar over the board for shavings. Slice with a long knife dipped in hot water and wiped dry.
   Look for The top is firm and glossy, and the rosettes hold their shape when touched.
   Tip Warm the knife between cuts and wipe it clean so each slice shows the layers clearly.

The finished ganache should look smooth, dark and glossy, with no streaks of cream or grainy spots. It should flow in a thick, even stream and settle into a level, shiny layer across the chopped cookies. Let the top set in the refrigerator for at least six hours or overnight before decorating. When lightly touched with a fingertip, the surface should feel firm and not sticky. Only then should you pipe the whipped cream rosettes and add the whole cookies and shavings.

Common mistakes

The most common mistake is baking the cheesecake at too high a temperature, which causes cracks across the top and a grainy, dry texture. Use a moderate oven and bake until the edges are set but the center still moves a little. Another mistake is overmixing the filling after the eggs are added, which traps air and can make the surface puff and crack as it cools.

Pouring the ganache onto a warm cheesecake will also cause it to slide and blur the layers, so wait until the filling is fully chilled. Finally, cutting into the cheesecake before it has set can smear the ganache and the cookie pieces, so give it the full chilling time before slicing.

How to tell it’s done

The cheesecake is done when the edges look set and firm, the surface is pale and smooth, and only the very center wobbles slightly when the pan is gently shaken. The filling should register 160°F (71°C) in the center when checked with an instant-read thermometer, which is the temperature at which the eggs in the filling are fully cooked.

Once baked, let the cheesecake cool slowly on the counter, then chill it until the ganache is firm and glossy. A cheesecake that is properly set holds clean slices and keeps its shape when lifted from the pan.

• Egg dishes: 160°F (71°C) in the thickest part