Quick Recipe Version (TL;DR)
Quick Ingredients
- 1.1 kg (2.4 lb) matambre/flank steak
- 7 cups (1.65 L) whole milk, plus up to 1 cup (240 ml) more if needed to cover
- 1 head garlic, halved crosswise
- 3 bay leaves
- 12 whole black peppercorns
- 2.5 tsp kosher salt, divided
- 0.5 tsp freshly ground black pepper
- 1 tbsp olive oil
- 2 tbsp unsalted butter
- 3/4 cup (180 ml) reserved milk cooking liquid, strained
- 1 tsp lemon juice
- 1 tsp Dijon mustard (optional)
- 2 tbsp chopped flat-leaf parsley
Do This
- 1. Season steak with 1.5 tsp salt and 0.5 tsp pepper; let sit 20 minutes while you gather ingredients.
- 2. In a snug pot, combine milk, garlic, bay, peppercorns, and 1 tsp salt; submerge steak.
- 3. Bring to a bare simmer (90–95°C / 195–203°F). Cook gently, partially covered, 1 hour 45 minutes, turning once.
- 4. Transfer steak to a tray; strain and reserve 3/4 cup cooking milk for sauce.
- 5. Pat steak very dry. Sear in hot skillet with 1 tbsp oil over medium-high, 2–3 minutes per side; add butter last 30 seconds to baste.
- 6. Deglaze pan with reserved milk; whisk in lemon juice (and Dijon, if using). Simmer 3–4 minutes to nappe consistency.
- 7. Slice steak thinly across the grain; spoon velvety pan juices over and finish with parsley.
Why You’ll Love This Recipe
- Ultra-tender beef: milk gently breaks down the flank steak into buttery slices without drying them out.
- Short ingredient list, huge flavor: garlic, bay, and peppercorns perfume the meat and sauce.
- Make-ahead friendly: the milk-braised meat slices beautifully and reheats like a dream.
- Weeknight-easy technique with weekend-level results.
Grocery List
- Produce: 1 head garlic, fresh flat-leaf parsley, 1 lemon
- Dairy: Whole milk (at least 7 cups), unsalted butter
- Pantry: Matambre/flank steak, bay leaves, whole black peppercorns, kosher salt, black pepper, olive oil, Dijon mustard (optional)
Full Ingredients
Beef
- 1.1 kg (2.4 lb) matambre/flank steak, trimmed
- 1.5 tsp kosher salt
- 0.5 tsp freshly ground black pepper
Milk Braise
- 7 cups (1.65 L) whole milk, plus up to 1 cup (240 ml) more if needed to cover
- 1 head garlic, halved crosswise
- 3 bay leaves
- 12 whole black peppercorns
- 1 tsp kosher salt
For Searing and Sauce
- 1 tbsp olive oil
- 2 tbsp unsalted butter
- 3/4 cup (180 ml) reserved milk cooking liquid, strained
- 1 tsp fresh lemon juice
- 1 tsp Dijon mustard (optional, for gentle tang)
To Finish
- 2 tbsp finely chopped flat-leaf parsley
- Flaky salt to taste (optional)
Step-by-Step Instructions
Step 1: Season and temper the meat
Pat the flank steak dry. Season both sides with 1.5 teaspoons kosher salt and 0.5 teaspoon black pepper. Let it rest at room temperature for 20 minutes. This brief rest helps the seasoning penetrate and ensures even cooking.
Step 2: Build the aromatic milk bath
In a snug, wide pot or deep sauté pan just large enough to fit the steak flat, combine 7 cups (1.65 L) whole milk, the halved head of garlic, bay leaves, peppercorns, and 1 teaspoon kosher salt. Nestle the steak in so it is submerged; add up to 1 cup (240 ml) additional milk or water only if needed to cover by about 1 cm.
Step 3: Poach low and slow
Set the pot over medium heat and bring the milk to a bare simmer—small lazy bubbles around the edges, 90–95°C (195–203°F). Reduce the heat to maintain this gentle simmer, partially cover, and cook for 1 hour 45 minutes, turning the steak once halfway through. The goal is tenderness, not a rolling boil. If the milk reduces too much, top up with a splash of hot water to keep the steak barely covered.
Step 4: Rest and reserve the cooking liquid
Transfer the steak to a tray and tent loosely with foil for 10 minutes. Strain the cooking milk through a fine-mesh sieve into a measuring jug, discarding aromatics. Reserve 3/4 cup (180 ml) for the sauce; the rest can be discarded or saved for another use. Pat the steak thoroughly dry—dry surfaces sear best.
Step 5: Sear for a flavorful crust
Heat a large heavy skillet (cast iron is ideal) over medium-high until hot. Add 1 tablespoon olive oil, then the steak. Sear 2–3 minutes per side until deeply browned. Add 2 tablespoons butter during the last 30 seconds and baste, tilting the pan so the foaming butter washes over the meat. Transfer steak to a cutting board to rest while you make the sauce.
Step 6: Make the velvety pan sauce
Pour off any excess fat, leaving browned bits in the pan. Add the reserved 3/4 cup strained milk cooking liquid. Bring to a brisk simmer, scraping up the fond. Whisk in 1 teaspoon lemon juice and, if using, 1 teaspoon Dijon for gentle tang. Simmer 3–4 minutes until the sauce lightly coats a spoon. If you prefer a thicker, glossier sauce, whisk 1 teaspoon cornstarch with 1 tablespoon cold milk and stir it in; simmer 30–60 seconds more. Taste and adjust salt as needed.
Step 7: Slice and serve
Slice the steak thinly across the grain (about 5 mm). Arrange on a warm platter, spoon the velvety pan juices over the top, and sprinkle with chopped parsley. Finish with a pinch of flaky salt if desired. Serve immediately with crusty bread or mashed potatoes to catch the sauce.
Pro Tips
- Keep the milk at a bare simmer; boiling can toughen the meat and split the milk. Gentle heat equals gentle texture.
- Use a snug pot so the steak stays submerged without needing excessive milk.
- Dry thoroughly before searing. Moisture is the enemy of browning.
- Straining the milk removes curds and aromatics, giving a smooth, velvety sauce.
- Slice across the grain for maximum tenderness—look for the long muscle fibers and cut perpendicular to them.
Variations
- Herb lift: Add a few thyme sprigs or a strip of lemon zest to the milk during the last 30 minutes.
- Smoky finish: After the braise, finish the sear on a hot grill for light char and smoke.
- Chimichurri drizzle: Serve with a spoonful of classic chimichurri alongside the milk sauce for a bright, Argentine touch.
Storage & Make-Ahead
Refrigerate cooled, sliced matambre with its sauce in an airtight container for up to 3 days. Reheat gently in a covered skillet over low heat with a splash of water or milk until warmed through. For make-ahead entertaining, complete the braise a day in advance, chill the steak in its cooking liquid, then sear, slice, and sauce just before serving. The cooked, sliced meat freezes well (up to 2 months); thaw overnight in the refrigerator and rewarm gently in sauce.
Nutrition (per serving)
Approximate: 380 calories; 24 g fat; 4 g carbohydrates; 35 g protein; 560 mg sodium.
