Roughly tear the bread into large pieces, then add to food processor. Add onion pieces and pulse a few times, until bread pieces are about pea-sized and onion is chopped.

Add garlic, salt, pepper, cayenne, cumin and eggs to food processor and pulse again until combined well.

Transfer contents to a large mixing bowl and stir in Guinness until a paste forms. Top with ground beef and use your hands to mix until just combined.

Use the side of your hand to lightly score the meat in half. Then score each half into 3 sections. Now you have 6 roughly equally sized sections. Scoop out the meat in each section and form into oval shaped patties.

Heat 1 Tbsp each butter and olive oil in a large skillet over MED HIGH heat. Once hot, add patties and sear about 4-5 minutes per side, until cooked through. Transfer patties to a plate and keep warm.

Reduce skillet heat to MED and add 1 Tbsp butter. Add sliced onions and cook for 5-8 minutes, until softened and starting to brown a little. Add garlic and cook 30 seconds.

Stir in beer and beef broth, scraping the bottom of the skillet to loosen any browned bits.

Add soy sauce, Worcestershire sauce, tomato paste, brown sugar, sriracha, smoked paprika, salt and pepper and whisk or stir to combine well.

In a small bowl combine cornstarch and water and whisk until smooth. Whisk mixture into the beef gravy and simmer until thickened to your liking, to where it at least coats the back of a spoon.

Add patties back to the skillet and spoon gravy over the top of the patties. Cook another minute or two, until everything is heated through.

Serve patties over mashed potatoes, with a generous spoonful or two of gravy over the top, sprinkled with fresh parsley if desired.