Cut off pointed end of garlic; place garlic on a piece of aluminum foil. Fold foil to seal.
Bake at 425° for 30 minutes; cool. Squeeze pulp from garlic cloves, and chop. Set aside.
Remove stems from mushrooms, and discard. Thinly slice mushroom caps.
Melt butter with oil in a 2-quart saucepan over medium-high heat. Add onion and mushrooms, and sauté 2 to 3 minutes. Add rice; sauté 1 minute. Stir in corn and wine; reduce heat to medium, and simmer, stirring constantly, until wine is reduced by half. Add 1/2 cup hot broth, and cook, stirring constantly, until liquid is absorbed. Repeat procedure with remaining hot broth, 1/2 cup at a time, until rice is tender. (Total cooking time is about 35 to 45 minutes.)
Stir in thyme and next 3 ingredients. Add cream cheese and chopped roasted garlic, stirring until blended. Serve immediately.