Dark Chocolate Oreo Cheesecake with Ganache and Whipped Cream Rosettes Step-by-step instructions

Before you start

Gather all the ingredients and equipment before you start, and set the cream cheese and eggs out on the counter about one hour before mixing so they reach room temperature. Preheat the oven to 325°F (163°C) and place the rack in the center position.

Wrap the outside of the 9-inch springform pan in two layers of heavy foil so no water can enter. Crush the cookies, measure the melted butter, and chop the dark chocolate so each step flows smoothly. Set a kettle of water to heat for the water bath. Keep the whipping cream chilled in the refrigerator until you are ready to whip it.

Instructions

Crust, filling and bake

1. 1Crush the chocolate cookies
   Stack the chocolate sandwich cookies and crush them finely in a food processor, or place them in a bag and crush them with a rolling pin. Reserve about 8 whole cookies for the top. Mix the crumbs with the melted butter until evenly moistened.
   Look for The crumbs look like damp dark sand and hold together when pinched.
   Tip Keep a few whole cookies aside before crushing so they are ready for the topping.
2. 2Press the crust into the pan
   Press the buttered crumb mixture firmly and evenly into the bottom of a 9-inch springform pan, bringing it slightly up the sides. Chill the crust while you prepare the filling so it firms up.
   Look for The crust is compact, with no loose crumbs on the pan floor.
   Tip Use the flat bottom of a measuring cup to press the crust into an even layer.
3. 3Chop and grate the dark chocolate
   Break the dark chocolate bar into pieces and chop them with a knife into small shards. Grate a portion of the chocolate on a box grater to make fine curls for the top, and set both aside.
   Look for Small shards and fine curls collect on the board.
   Tip Chill the chocolate briefly before grating so the curls hold their shape.

The crust is compact and firm to the touch, and the cream cheese filling is smooth, pale and evenly spread across the surface. Before going on, check that no lumps remain in the batter and that the springform pan is wrapped tightly in foil.

Once baked, the edges should look set while the center moves only slightly when the pan is tapped. The cheesecake should smell mildly sweet and creamy, with no scorched or burnt aroma from the oven. Let it cool undisturbed in the oven before removing it, so the surface stays smooth and free of cracks.

Ganache and toppings

4. 4Beat the cream cheese filling
   Beat the softened cream cheese and sugar in a large bowl until smooth and free of lumps. Add the eggs one at a time, mixing on low speed after each, then stir in the sour cream and vanilla extract until just combined.
   Look for The filling is smooth, pale and evenly combined, with no streaks of cream cheese.
   Safe temperature 160°F (71°C) internal temperature (egg dishes)
   Tip Scrape down the bowl often so no lumps remain in the filling.
5. 5Fill and bake the cheesecake
   Spread the pale cream cheese filling smoothly over the chilled crust. Set the springform pan in a larger pan filled with hot water and bake at 325°F (163°C) for about 55 to 60 minutes, until the edges are set and the center barely jiggles. Turn off the oven, crack the door and let the cheesecake cool inside for one hour.
   Look for The edges are set and the center moves only slightly when the pan is tapped.
   Safe temperature 160°F (71°C) internal temperature (egg dishes)
   Tip Wrap the outside of the springform pan in foil to keep water out.
6. 6Make the dark chocolate ganache
   Bring the heavy cream to a gentle simmer in a small saucepan. Pour it over the chopped dark chocolate, let it stand for two minutes, then whisk until smooth and glossy.
   Look for The ganache is smooth, glossy and pourable, with no visible chocolate pieces.
   Tip Let the ganache cool for a few minutes so it thickens slightly before pouring.

The cooled cheesecake has a firm, level surface ready for the ganache. The ganache should be smooth, glossy and fluid enough to pour, with no grainy bits of chocolate left. Check that the ganache is cool enough that it will not melt the surface of the filling, but still spreads easily toward the edge. The cookie crumbs and whole sandwich cookies should be scattered evenly across the top before the grated chocolate curls are added. The surface should look dark, shiny and balanced, ready for the final garnish.

Whipped cream and slicing

7. 7Pour the ganache and add toppings
   Pour the glossy dark chocolate ganache over the center of the cooled filling, leaving a border. Scatter the crushed cookie crumbs and the reserved whole sandwich cookies over the top, then sprinkle with the grated chocolate curls.
   Look for The ganache spreads toward the edge in a glossy, even layer.
   Tip Pour slowly from the center so the ganache settles without running over the sides.
8. 8Pipe the whipped cream rosettes
   Whip the cold heavy cream with the confectioners' sugar until stiff peaks form. Spoon the cream into a piping bag fitted with a star tip, and pipe rosettes around the edge of the cheesecake.
   Look for The cream holds stiff peaks that keep their shape when lifted.
   Tip Chill the whipped cream until piping so the rosettes hold their shape.
9. 9Chill, slice and serve
   Refrigerate the cheesecake for at least six hours or overnight until firm. Run a knife around the edge, release the springform ring, and slice with a clean, warm knife. Lift each slice with a spatula to serve.
   Look for The cheesecake is firm and the slices hold a clean, dense shape.
   Tip Dip the knife in hot water and wipe it between cuts for neat slices.

The whipped cream holds stiff peaks that stand upright when the whisk is lifted, and it pipes into clean, defined rosettes around the edge. Before cutting, check that the cheesecake has chilled for at least six hours, so the slices hold a firm, dense shape. The knife should move through the filling without dragging, and each slice should lift onto a spatula cleanly. The interior should look smooth, creamy and evenly colored, with a clean crust layer at the base.

Common mistakes

The most common mistake is working with cold cream cheese, which leaves small lumps that stay in the batter and show as specks in the finished slices. Another frequent problem is overbeating the filling after the eggs go in, which adds air and can cause cracks in the surface as the cheesecake bakes and cools.

Skipping the foil around the springform pan lets water seep into the crust, making it soggy at the bottom. Pouring the ganache onto a warm cheesecake can melt the filling and leave a greasy layer. Cutting the cheesecake too soon, before it has chilled, produces ragged slices that lose their shape. Finally, whipping cream until it turns grainy ruins the piping, so stop as soon as stiff peaks form.

How to tell it’s done

The cheesecake is done when the edges are set and the center still moves slightly when the pan is gently tapped, which means it will finish firming as it cools. For the filling, the eggs are cooked through when the batter reaches 160°F (71°C) at the center, which is the safe temperature for eggs in this recipe.

An instant-read thermometer inserted near the center without touching the pan gives a reliable reading. After cooling and chilling, the cheesecake should be firm, dense and creamy when sliced, holding a clean edge with no wobble in the middle. The ganache should be set and glossy on top before the whipped cream is piped.

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