2 - 6 cup silicone muffin pans set on a wire baking rack and placed into a sheet pan Or 1 - 12 cup muffin tin.

For the silicone muffin pans - lightly coat the muffin pans with cooking spray then place them on a wire rack set in a baking sheet.

For the muffin tin - coat each muffin cup with shortening or butter and cut small circles of parchment paper to set in the bottom of each cup. Lightly spray each cup with cooking oil spray.

Set the oven rack in the middle of the oven and pre-heat the oven at 350˚ F/175˚ C/Gas Mark 4. Let the oven heat up for twenty minutes before you toast the walnuts.

Spread the walnut halves evenly over a small baking sheet, place in the oven and toast the walnuts to bring out the oils and enhance their flavor. Toast for 7 minutes turning the walnuts over a couple of times while baking.

When finished spread the toasted walnuts over a clean lint free dish towel and fold one end over the walnuts to cover. Place your hands over the covered walnuts and gently rub back and forth to loosen and remove the walnut skin. Rub off as much of the walnut skins as you can and place the walnuts in the bowl of a food processor. Discard the skins.

Lower the oven temperature to 225˚ F/107˚ C

Pulse the food processor to finely chop the walnuts. You want an even consistency without turning the walnuts into flour.

Spoon 1 Tb of ground walnuts into each muffin cup and press down evenly to pack the walnuts together.

Using a stand mixer or hand held mixer, mix the sugar, cornstarch and salt until just mixed together. Add the cream cheese and beat on low speed until the ingredients are evenly combined. Increase the speed to medium and beat until very smooth, about 1 minute. Scrape the batter down the sides of a bowl.

In a small bowl, mix together the sour cream and blue cheese until evenly combined. A fork is great for this job. Add the blue cheese mixture to the cream cheese and mix together on low speed until just combined, about 15 seconds.

Add the lightly beaten eggs and mix until evenly combined. The batter consistency should resemble sour cream.

Pour the cheesecake batter into each muffin cup almost up the top, about 1.8 oz/50 g in each muffin cup. Smooth over the tops of each cheesecake with an offset spatula.

Bake in the 225˚ F/107˚ C oven for 15 minutes. Rotate the muffin pan in the oven from front to back to encourage even baking and bake for 15 to 20 minutes longer. The muffins are done when an instant read thermometer reads 160˚ F/71˚ C. The batter will jiggle somewhat and the centers of each muffin will spring back when touched. Put muffin tin and/or baking sheet on a cooling rack.

Allow the cheesecakes to cool in the muffin pan for 30 minutes. Cover the muffin pan(s) with plastic wrap lightly coated with cooking spray and refrigerate for at least 4 hours before unmolding.

For the metal muffin pan: run a small spatula or knife, heated up with hot water, around the edge of each muffin cup. Press the spatula or knife up against the side of the pan to not scrape the sides of the cheesecakes. Clean the spatula with warm water and wipe clean with a cloth for every cheesecake. Lift the cheesecakes out of the muffin cups with a spatula. Smooth the sides of each cheesecake using a small metal spatula that has been heated with hot water and wiped clean.

For silicone muffin pans: Rose Levy Beranbaum recommends placing a baking sheet on top of the plastic wrap-covered muffin pan and turn it upside down. Then place a dish towel in very hot water. Wring out the excess water and drape it over the muffin pan. Make sure to press the hot wet towel into the recesses of the pan. Let it sit for about 2 minutes. Remove the towel and carefully lift off the muffin pan. If the cheesecakes do not release, repeat the above steps, and try again after another minute. Once released, place a second sheet pan on top of upside down cheesecakes and turn them right side up.

Place the cheesecakes on a serving platter and serve.

Store, refrigerated for up to 5 days.