Preheat oven to 175C (350F). Season the roast with salt and pepper to taste.
In a cast iron pot or Dutch oven, melt two of the three tbsp of butter. Brown the roast on all sides in the butter.
When the roast is browned, add wine, sage, bay leaf, onion, and garlic. Optionally add red pepper flakes and additional salt. Cover the pot and place roast in the oven for 23 hours, or until desired level of doneness.
Melt remaining 1 tbsp of butter in a small saucepan on medium heat. Mix 1 tbsp of flour until well combined. Reduce heat to low until roux is lightly browned, being careful not to burn it. Season with sage, salt, and pepper to taste.
Add cup of water, and remaining liquid from roast including onions and garlic. Rise heat to medium, bring to a boil and lower to low heat, simmering until gravy thickens.
Slice roast and serve topped with gravy.
