Melt butter and add onions Cooke for two to three minutes until translucent. Add flour and stir constantly for three to four minutes on medium low heat to cook the flour. Add stock and heavy cream, and season to taste mix thoroughly. Toss in broccoli and carrots and cover. Simmer for 20 minutes, add cheese and simmer for additional 5 minutes. Taste adjust seasoning to liking and serve in a bread bowl or even on its own! Enjoy