In a medium, heavy-bottomed saucepan, slowly warm milk with lavender and vanilla, bringing just up to simmering range before turning off heat. The mixture should have steeped for about 15 minutes during this process. While milk is heating, whisk together egg yolks and sugar in a small bowl. Slowly whisk about 1 cup of the hot milk into the egg mixture; this will “temper” the eggs so they will not easily curdle later. Then slowly whisk the warm egg mixture into the rest of the hot milk.

Return the saucepan to the stove over medium-low heat, and stir constantly while the mixture heats and thickens. At about 175° the sauce will be thick enough to cling to the back of a spoon. Remove it from heat and strain into a clean bowl.

Custard sauce can be served immediately. If storing to serve later, allow to cool, stirring occasionally to release steam and prevent a skin from forming, then refrigerate, covered tightly.

Lavender Ice Cream

Use the recipe above but for the whole milk substitute at least half cream, use 5 egg yolks, and reserve a few of the lavender flowers from steeping, adding them to the strained custard at the end. Chill the custard fully—at least 6 hours—then freeze in an ice cream maker.