Cornflour Sauce Recipe: Velvety Thickening for Gravies and Stews

This cornflour slurry technique transforms thin liquids into velvety, restaurant-quality sauces with minimal effort. I’ve used this method for years to thicken gravies, stews, and casseroles without altering their natural flavors.

Mixing cornflour with cold water first prevents lumps, while gradual whisking into hot liquid ensures a smooth, glossy finish. It’s a foolproof way to achieve the perfect consistency every time.

Ingredients for Cornflour Sauce

Eight simple ingredients transform any liquid into a silky, restaurant-quality sauce base.

The cornflour must be fresh for optimal thickening power—check the expiration date. Bob’s Red Mill offers a reliable, consistently fine grind. Cold water is non-negotiable for the slurry; warm water causes premature thickening and lumps. For the vegetable stock, Better Than Bouillon paste (vegan variety) provides excellent flavor without added sodium concerns.

No cornflour? Arrowroot powder at a 1:1 ratio works similarly, though it creates a slightly clearer sauce. For a gluten-free roux alternative, mix rice flour with cold water. The vegan butter can be omitted for oil-based sauces, but it adds a luxurious mouthfeel. If using fresh garlic and onion, sauté in the butter before adding liquid.

The slurry keeps for 1 hour at room temperature before use. Prepared sauce stays fresh in the fridge for 3-4 days or can be frozen for 2 months. Stir thoroughly when reheating, as separation may occur.

Step-by-Step Instructions for Cornflour Sauce

Master this technique for a smooth, velvety sauce with professional consistency every time.

Step 1: Create the Cornflour Slurry

In a small bowl, combine the 2 tbsp Cornflour with the 2 tbsp Cold Water. Whisk vigorously until completely smooth, with no visible lumps remaining. I’ve found that using cold water prevents premature thickening and ensures the cornflour disperses evenly.

The slurry should resemble thin, milky liquid. If you notice any clumps, keep whisking until they dissolve completely. This step is crucial—properly mixed slurry prevents lumps in your final sauce.

Step 2: Heat the Vegetable Stock

In a medium saucepan, bring the 2 cups Vegetable Stock to a gentle simmer over medium-high heat. Stir in the 0.5 tsp Garlic Powder, 0.5 tsp Onion Powder, 0.25 tsp Sea Salt, and 0.25 tsp Black Pepper until fully dissolved.

Watch for small bubbles to form at the edges of the pan and a slight steam to rise from the surface. This indicates your stock is at the perfect temperature for the next step. Don’t allow it to reach a rolling boil, as this can affect the thickening process.

Step 3: Temper and Thicken the Sauce

Slowly pour the cornflour slurry into the simmering stock while whisking constantly. The mixture will immediately begin to thicken. Continue whisking for 1-2 minutes as the sauce transforms from thin liquid to a velvety, glossy consistency.

You’ll notice the sauce coating the back of a spoon thickly, with a ribbon-like texture when it drizzles. If it’s too thick, add a splash more stock; if too thin, a small additional slurry (equal parts cornflour and water) can be whisked in.

Step 4: Finish with Vegan Butter

Remove the sauce from heat and stir in the 1 tbsp Unsalted Vegan Butter until fully melted and incorporated. This final step adds a beautiful sheen and rich mouthfeel to the sauce.

The sauce should now have a smooth, satiny appearance with a consistency that coats the back of a spoon but still flows easily. Taste and adjust seasoning if needed, though remember the flavors will intensify slightly as the sauce cools.

Essential Equipment for This Dish

Whisking Tools

Start with a small mixing bowl for your slurry—8-12 oz capacity works perfectly. I swear by my OXO Good Grips bowl set; the non-slip base keeps things steady while whisking. A mini whisk (like the Ateco 8-inch) is ideal for mixing the cornflour and water without lumps. 💡

Saucepan Selection

Use a medium saucepan (about 2-3 quarts) with a heavy base to prevent hot spots. My go-to is the All-Clad Stainless Steel—it distributes heat evenly and responds well to temperature changes. Avoid nonstick pans here; the metal whisk can scratch the surface.

Measuring Essentials

Precision matters, so use proper measuring spoons and cups. I love the King Arthur Measuring Spoons for the cornflour and seasonings—they nest neatly and have clear markings. For liquids, a glass measuring cup with a spout makes pouring the slurry a breeze.

Thermometer Option

While not strictly necessary, an instant-read thermometer helps maintain the perfect simmer at 180-190°F. The ThermoWorks ThermoPop is my budget-friendly choice—it gives accurate readings in 3-4 seconds. This prevents overheating your sauce.

Storage Containers

For leftover sauce, use airtight glass containers—I prefer Pyrex with snap-on lids. They’re microwave-safe and won’t absorb odors. For freezing, silicone muffin cups let you portion the sauce for easy future use. ✨

Specialty Addition

If making larger batches regularly, consider a fat separator for skimming off any excess oil from your stock. The OXO Good Grips model has a handy measurement markings and a comfortable grip. It’s a game-changer for achieving perfectly smooth sauces.

Frequently Asked Questions