Cream of Broccoli Soup: Gluten-free

I've outdone myself. Best soup I think I have ever eaten. I will admit that this is a Martha makeover, but the modifications that I made are both GF, and I think a little tastier. It's worth the effort and then some.

Level of Difficulty: Anita

5 tablespoons unsalted butter
1 medium onion chopped
1 heaping Tablespoon all-purpose gluten-free flour
4 cups (32 oz.) chicken stock
1 3/4 lbs. broccoli; trimmed and cut into florets, peel and cut stems cross-ways into 1/4 inch pieces (keep stems and florets separate)
1 1/2 teaspoons course sea salt
ground pepper to taste
1 cup heavy cream

Directions:
Sauté butter and onions on medium heat in wok/skillet for five minutes. Add flour and stir constantly for one minute. Transfer to a stock pot and add chicken stock. Whisk on medium heat for about three minutes and lower the heat to low. Simmer, whisking often, for ten minutes. Add broccoli stems and bring to a boil. Add broccoli florets. Add salt and pepper, then reduce heat to low and simmer for 18-24 minutes, stirring occasionally (keep covered). Pour soup into blender and purée (you may have to do this in 2-3 parts). Pour puréed broccoli mix back into the stock pot. Add heavy cream, and whisk thoroughly. Serve to a happy crowd.