Bring the 7 cups of chicken broth just to the boil. Turn heat to low, cover, and hold until needed.
In a large heavy pot, melt butter over medium heat. Sauté onion for about 4 to 5 minutes, or until translucent. Add garlic and sauté for another 2 to 3 minutes. Add corn and 2 tsp. of the rosemary. Stir and heat for 3 to 4 minutes, ensuring that the butter coats everything.
Add the rice and stir well for 2 to 3 minutes to blend the ingredients and coat the rice with the butter.
Add the wine and simmer for about 1 minute, until the wine has evaporated.
Add the 7 cups of hot stock all at once and stir well for 30 seconds. Bring to a boil, reduce heat, and let simmer uncovered, until rice is just tender, stirring occasionally, about 15 to 18 minutes. Risotto should be creamy and a bit soupy. Add more broth, ¼ cup at a time, if risotto doesn’t seem creamy enough.Take care not to overcook — the rice should be tender but not mushy.
Stir in baby spinach leaves, cream, and Parmesan cheese. Season to taste with salt and pepper.
Transfer risotto to a serving bowl and sprinkle with the Asiago and remaining rosemary.