Start by thinly slicing 1 lb of beef sirloin against the grain. Clean and slice 2 cups of mushrooms — shiitake or cremini work beautifully here. Mince 4 cloves of garlic and chop 3 green onions for garnish. Set everything aside for a smooth cooking process.
Bring a pot of water to a boil and add the udon noodles. Cook according to package instructions, usually 8-10 minutes, until they’re tender but still chewy. Drain the noodles and set them aside — a quick rinse under cold water can help prevent sticking.
In a large skillet over medium heat, melt 2 tablespoons of unsalted butter. Add the minced garlic and sauté for about 30 seconds until fragrant. Toss in the mushrooms and cook until they release their juices and become golden brown, about 5-7 minutes.
Push the mushrooms to the side of the skillet and add a little more butter if needed. Increase the heat to medium-high and add the thinly sliced beef sirloin. Sprinkle with salt and pepper, and stir-fry until the beef is browned and just cooked through, about 3-4 minutes. Mix the beef and mushrooms together.
Add the cooked udon noodles to the skillet and drizzle 3 tablespoons of soy sauce and 1 tablespoon of sesame oil over everything. Toss gently to combine all the ingredients well and let the noodles soak up the flavorful garlic butter sauce for a minute or two.
Remove from heat and sprinkle the chopped green onions on top for a fresh, vibrant finish. Serve your Beef Mushroom Udon with Garlic Butter hot, and enjoy the irresistible aroma and taste of this hearty, savory dish.
