Summer risotto of corn, wild mushrooms, and spinach

Having picked up some shiitake mushrooms at the Farmer's Market last week, I set about finding a seasonal recipe in which to use them. After searching for a while, I came across a recipe on Epicurious.com for Roasted Corn, Wild Mushroom, and Spinach Risotto. We love risotto and Mike adores fresh corn. I was also sold on the fact that it was a hometown recipe. It is from Boulevard, a very upscale restaurant in San Francisco. It was more work than I anticipated, but it turned out marvelously!

Roasted Corn, Wild Mushroom, and Spinach Risotto
adapted from Epicurious, Bon Appetit, Boulevard, September 1997
Serves 5-6, in my opinion, the recipe said 4

4 ears of fresh corn that has been husked
4 tbsp olive oil
2 cups of wild mushrooms thinly sliced (I used shiitake and oyster mushrooms)
2 tbsp, fresh thyme, chopped
6 cups of chicken stock
1 1/4 cups chopped onion
1 1/2 cups of arborio rice
1/4 cup dry white wine
2 cups of baby spinach, stems removed
2 tbsp grated Parmesan cheese
1 tbsp butter
2 tbsp chopped chives or green onions

Preheat the oven to 400 degrees. Place the husked corn on a baking sheet. Brush or rub the ears with olive oil. Roast the corn in the oven until tender and brown in spots. Turn the ears occasionally and roast for about 40 minutes. Remove the corn from the oven and let cool to the touch. Cut the corn kernels off the cobs. Reserve 1 cup of the corn kernels. Combine the remaining corn and 1/2 cup of chicken stock in a food processor or blender. Blend until almost smooth. Set puree aside for later use. This entire step can be done in advance and refrigerated.
Toss the sliced mushrooms with the chopped thyme and 1 tbsp of olive oil on a large baking sheet. Sprinkle with salt and pepper. Roast mushrooms until tender and they are beginning to turn golden, stirring once. This will take about 15 minutes.

Bring 5 1/2 cups of chicken stock to a simmer in a large pot. Reduce heat to low and keep the stock hot.

Meanwhile, prep the remaining ingredients. Then heat 2 tablespoons olive oil in a large saucepan over medium heat. Add the onion and saute for 2-3 minutes. Add rice; stir for 3 more minutes. Add wine, stir until liquid is absorbed. This will take 1-2 minutes. Add 1 cup of the stock. Simmer and stir until the liquid is absorbed. Add a 1/2 cup of the stock at a time thereafter. Simmer until stock is absorbed before each 1/2 cup addition of the stock. Stir mixture frequently. You are looking for tender rice that is still slightly firm in the center and the mixture looks creamy. Taste rice grains as you go. Mix corn puree, reserved corn kernels, half the mushrooms, spinach, Parmesan cheese, and butter into the risotto. Stir in the last 1/2 cup of chicken stock to moisten, if necessary. Season with salt and pepper. Remove from heat. Serve risotto in soup bowls and topped with remaining mushrooms and a sprinkling of chives or green onions.