In a sauté pan over medium heat, melt 3 tbsp butter. Add leeks and cook until soft, then add garlic, salt, pepper, and herbs. Cook for a minute, then slowly add flour, stirring constantly. Add Eliot Ness Amber Lager to pan and scrape up browned bits. Pour mixture into a slow cooker with stock and bay leaf and cook on low for 8 hours or high for 4 hours. In a separate pot, boil potatoes. Remove half of the potatoes and combine them in a bowl with 1/2 C heavy cream and 2 tbsp butter. Mash or whip the potatoes until smooth, then transfer to the slow cooker with the broth. Add remaining unmashed potatoes and heavy cream. Gradually mix in cheeses, stirring until melted. Cook for another 20 minutes and garnish with bacon and green onions.