Equipment
Ingredients
Mustard Base
- 50 g mustard powder
- 50 ml cold water
Custard Base
- 50 ml white vinegar
- 1 egg, room temperature
- 30 g white sugar
- 3 g fine sea salt
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 38 kcal
- Protein
- 2 g
- Carbohydrates
- 4 g
- Fat
- 2 g
- Fiber
- 1 g
- Sugar
- 3 g
- Sodium
- 104 mg
- Saturated Fat
- 0 g
- Monounsaturated Fat
- 1 g
- Polyunsaturated Fat
- 1 g
- Cholesterol
- 16 mg
- Potassium
- 37 mg
- Calcium
- 14 mg
- Iron
- 0.5 mg
- Magnesium
- 16 mg
- Phosphorus
- 43 mg
- Zinc
- 0.3 mg
- Vitamin A
- 7 mcg
- Vitamin C
- 0 mg
- Vitamin D
- 0.1 mcg
- Vitamin E
- 0.3 mg
- Vitamin K
- 0 mcg
- Vitamin B6
- 0.0 mg
- Vitamin B12
- 0.0 mcg
- Thiamin
- 0.04 mg
- Riboflavin
- 0.03 mg
- Niacin
- 0.2 mg
- Folate
- 9 mcg
- Water
- 12 g
Sources: Aggregated Public Data, USDA FoodData Central
Method
In a small mixing bowl, combine the mustard powder and cold water. Mix thoroughly until a thick, uniform paste forms.
Allow the mustard paste to sit undisturbed at room temperature for exactly 10 minutes to allow the myrosinase enzyme to develop the pungent heat.
While the paste rests, combine the white vinegar, room temperature egg, white sugar, and fine sea salt in a heatproof bowl. Whisk vigorously until the sugar begins to dissolve and the mixture is frothy.
Add the rested mustard paste into the egg mixture. Whisk them together until completely homogenous.
Place the heatproof bowl over a saucepan of barely simmering water to create a double boiler. Whisk the mixture constantly until it thickens slightly and a thermometer registers 71°C/160°F, ensuring the egg is safely cooked without scrambling.
Remove the bowl from the heat immediately. Allow the hot mustard to cool to room temperature before transferring it to a storage jar.
Chef's Notes
- The heat of mustard powder is unlocked by an enzymatic reaction that requires cold water. Warm water, acid, or immediate heat will denature the enzyme and result in a bitter, mild mustard.
- Vinegar is added after the heat develops to stabilize the mustard. Once the acid is introduced, the heat level is permanently locked in.
- Using a double boiler instead of direct heat is critical when making egg-based sauces to prevent the proteins from coagulating too quickly and scrambling.
- This mustard will continue to thicken slightly as it cools in the refrigerator due to the egg content.
Storage
Refrigerator: 2 weeks — Store in an airtight glass jar.
Troubleshooting
Mustard has no heat or kick
Cause: Used warm water or skipped the 10-minute resting phase before adding vinegar or heat
Fix: Cannot be fixed
Prevention: Always hydrate dry mustard powder with ice cold water and rest for 10-15 minutes to fully activate the enzymes.
The mixture contains cooked egg lumps
Cause: Heat was too high or whisking was insufficient while cooking
Fix: Pass the mustard through a fine mesh sieve before it cools completely.
Prevention: Keep the water in the saucepan at a gentle simmer, not a rolling boil, and whisk constantly without pausing.
Cultural Context
The technique of balancing fiery mustard powder with egg and sugar has roots in old English and early American colonial recipes, sometimes referred to as prepared mustard or mustard sauce. By cooking the mixture gently like a savory custard, the intense bite of the mustard seed is smoothed out, creating a rich condiment that pairs exceptionally well with glazed hams, sausages, and strong cheeses.
