Steak Dip Recipe

Prepare and season steak

Pat the steak dry with paper towels. Season both sides evenly with kosher salt, black pepper, and garlic powder. Let rest at room temperature while you prepare vegetables (10–15 minutes).

Slice vegetables

Peel and thinly slice the onion into half-moons. Clean mushrooms with a damp cloth and slice them about 1/4" thick.

Sear steak

Heat 1 tablespoon olive oil in a large skillet or cast-iron pan over medium-high heat until shimmering. Add the steak and sear 3–4 minutes per side for medium-rare (adjust time for thickness and desired doneness). Use tongs to get good contact; do not move the steak while searing. Remove steak to a cutting board and tent loosely with foil. Let rest 5–8 minutes before slicing thinly against the grain.

Cook onions and mushrooms

Using the same skillet, reduce heat to medium and add 1 tablespoon olive oil and 1 tablespoon butter. Add the sliced onions and a pinch of salt; cook 6–8 minutes until soft and beginning to caramelize, stirring occasionally. Add the sliced mushrooms and cook another 5–6 minutes until browned and their liquid has evaporated. Stir in minced garlic and thyme in the last minute of cooking. Season to taste with additional salt and 1/4 tsp black pepper. Remove from pan and keep warm.

Slice steak thinly

When steak has rested, slice it thinly across the grain into bite-sized strips or thin slices suitable for piling into a hoagie.

While the steak rests or right after removing it from the pan, lower heat to medium-low. Add the minced shallot to the skillet drippings and cook 1–2 minutes until softened. Pour in 2 cups beef stock and scrape the bottom of the pan with a wooden spoon to deglaze and lift browned bits (fond). Add 1 tablespoon soy sauce or Worcestershire and 1 teaspoon beef base if using. Bring to a gentle simmer and reduce 5–8 minutes to concentrate flavors slightly. Taste and adjust seasoning with up to 1/4 tsp more salt or pepper. For a glossy finish, whisk in 1 teaspoon cold butter just before serving. Keep warm in a small pot or transfer to a dipping bowl.

Preheat oven broiler or set oven to 400°F (200°C) to toast the hoagies. Split the rolls horizontally, keeping one side attached if desired. Brush cut sides lightly with the reserved 2 tablespoons butter (melt if needed).

Place rolls cut-side up on a baking sheet and toast under the broiler or in the oven for 2–4 minutes until golden and crisp — watch carefully to prevent burning.

Pile sliced steak evenly into the toasted hoagies, then top with generous portions of the sautéed onions and mushrooms. Sprinkle shredded or sliced mozzarella evenly over the hot filling. If you want the cheese melted and bubbly, return assembled sandwiches to the oven for 1–2 minutes under the broiler or at 400°F until cheese melts.

Garnish with chopped parsley and a pinch of red pepper flakes if using. Serve immediately with individual bowls or a small pitcher of the house-made au jus for dipping.