Mustard Sauce

Name: Mustard Sauce
Prep time: 5 min
Cook time: 10 min
Total time: 145 min
Ingredients: 2 large eggs; ½ cup brown sugar; ¼ teaspoon salt; ½ cup milk; 4 tablespoons dry mustard; ¼ cup butter or margarine (½ stick), cut into 4 pieces; 2 tablespoons distilled white vinegar

A gentle stovetop cook gives dry mustard a creamy, lightly sweet body instead of a harsh edge. After a night in the refrigerator, it spreads smoothly over a slice of holiday ham.

By Betty Lou Gardner2 hr 25 minUpdated 2026-08-25

This Mustard Sauce is smooth, creamy, and pleasantly tangy, with a balance of sweetness and sharp mustard flavor that makes it a versatile condiment for sandwiches, roasted meats, and holiday meals! Chilled until thick and spreadable, it brings a rich, old-fashioned touch to everything from ham to deviled eggs.

Betty Lou Gardner in a family archival photograph

Granny’s Kitchen Notes

From Betty Lou Gardner

I usually make this a day ahead because I think the flavor settles down nicely after a night in the refrigerator. We seem to pull it out most often when there's a ham on the table, but somebody always finds a reason to spread a little on a sandwich before the meal even starts. It never stays in the refrigerator very long once the family knows it's there.

How to Make Mustard Sauce

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Eggs, brown sugar, milk, salt, and dry mustard whisked together in a vintage saucepan.

Whisk the Base Ingredients

Combine the eggs, brown sugar, milk, salt, and dry mustard in a heavy saucepan until completely smooth.

Golden mustard sauce being whisked over low heat as it thickens in a vintage saucepan.

Cook Gently Until Thickened

Cook over medium-low heat, whisking constantly, until the sauce coats the back of a spoon, small bubbles appear around the edge, and it reaches at least 160°F.