Heat the oven to 350 degrees. Line a baking sheet with parchment paper. 

Cut the broccoli into florets and place in a large mixing bowl. Coat in 1 tbsp of olive oil and season with salt and pepper. Spread the florets on the baking sheet and roast for 25 minutes, or until roasted and just starting to brown. 

Remove the broccoli from the oven. Reserve 1/4 of the broccoli in a bowl. Set the bowl and sheet pan aside to prep the rest of the soup. 

In a heavy bottomed pot, heat 1 tbsp of olive oil on medium heat. Add the onion and cook for about 12 minutes stirring frequently. Cook until the onion is translucent. 

Add the garlic and cook for 10 seconds. Add 3/4 of the roasted broccoli. Finally add the chicken stock and heat until hot. 

Add the contents of the pot to a Vitamix or other food processor/blender. Blend for 2 to 3 minutes until creamy and smooth. Then add the lemon and parmesan. Pulse a couple more times to incorporate. 

Add the contents of the Vitamix back to the stock pot. Add the reserved 1/4 of roasted broccoli. Stir to incorporate. 

Serve piping hot in bowls. Garnish with shaved parmesan and a dash of lemon juice. This soup goes great with roasted chicken or steak.