Pear-Walnut Upside-Down Cake

I have to admit I love upside down cakes, they are loaded with fruit and you don't have to ice them. This recipe is based on a recipe from America's Test Kitchen. I have modified it to suit my tastes and to work better with 100% whole grains. Fall is the perfect time for pears and this cake really shows them off.

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Oven: 300 degrees
Bake: 70 - 75 minutes
Pan: 9 inch round cake pan (best if light in color) Lined with parchment paper

Ingredients:
Topping
4 T. unsalted butter, melted (57g)
1/2 c. brown sugar (100g)
2 tsp. cornstarch
1/8 tsp. salt
3 ripe but firm Bosc pears  about 1.5 pounds (680g)

Cake
1 c. walnuts, toasted
1/2 c. Soft White Berries - Pastry Flour (75g)
1/2 tsp. salt
1/4 tsp. baking powder
1/8 tsp. baking soda
1/2 tsp. cinnamon
1/2 tsp. ginger
1/4 tsp. cloves

3 large eggs
1 c. sugar (200g)
4 T. unsalted butter, melted  (57g)
1/4 c. vegetable oil (56g)
1 tsp. vanilla

Directions:
Toppings

• Grease the 9 inch round cake pan and line the bottom with parchment paper. Pour the melted butter over the bottom of the pan and swirl to evenly coat. Combine the sugar, cornstarch and salt in a small bowl and sprinkle evenly over the melted butter.
• Peel, half, and core the pears. Set aside 1 pear half and reserve for another use. Cut the remaining 5 pears halves into 4 wedges each. Arrange the pears in a circular pattern around the cake pan with tapered ends pointing inward. Arrange the two smallest pear wedges in the center.

Cake

• Pulse the walnuts, flour, salt, spices, baking powder and baking soda in a food processor until the walnuts are finely ground. This will take about 8-10 pulses. Transfer this mixture to  a small bowl.
  
• Process the eggs, vanilla and sugar in the now empty food processor until very pale yellow, about 2 minutes. With the food processor running add the melted butter and oil in a steady stream until incorporated.
  
• Add the walnut mixture and pulse to combine about 4-5 pulses. Pour batter evenly over the pears. Some pear may be showing through, that is OK the batter will bake up over the pears.
• Bake until the center of the cake is set and bounces back when gently pressed and a toothpick inserted in the center comes out clean, about 70 minutes. You may need to rotate the cake half way through the baking process to cook evenly.
• Let the cake cool in the pan for 15 minutes. Then run a knife around the sides of the pan and invert the cake onto a wire rich. Remove the parchment paper and let the cake cool completely about 2 hours