Place a large pot of salted water on the stove and bring to a low boil. Add the broccoli and peeled garlic and cook until bright green and fork tender, about 10-15 minutes. Add 8 ounces of peas and cook for 2 minutes until bright green. Drain into a sieve and return the pot to the stove.
Melt the butter into the pot over medium heat. Once melted and frothy add the broccoli and peas.
Season all over with salt, pepper, and crushed red pepper and add the stock and cream. Reduce heat to low. Using an immersion blender (or transfer to traditional blender), blend the purée until desired consistency is reached, adding more stock or cream as necessary, depending on preference.
Add the remaining 2 ounces of peas and cook over low heat for 5-7 more minutes. Taste and season again. Remove the purée from the heat and keep warm. Right before serving, stir the purée again and season to preferences.