Heat oven to 350 degrees.
Cut top off garlic bulb, place cut side up in baking dish, drizzle with olive oil.
Roast for about 20-25 minutes. (bulb will be very soft when squeezed).
While garlic is roasting, place tomatoes in large pot of boiling water.
Boil just until skins burst and separate. (3-5 minutes)
Peel skin from tomatoes, and chop into pieces, set aside.
In large pot heat 1 tbsp. olive oil, add diced onions and sauté medium/low heat until golden.
Stir in tomatoes, broth, and basil.
When garlic is roasted, gently squeeze garlic out of skin and add to soup.
Simmer soup for 40 minutes.
With immersion blender puree soup.
Add cream and simmer for additional 10 minutes.
Season with fresh ground pepper.
Garnish with crostinis topped with melted parmesan cheese.