Put boiling water, butter and lard in a large saucepan, and when it boils turn in flour. Beat well with a vegetable masher. When perfectly smooth remove from the fire, and as soon as cold break into it 5 eggs, 1 at a time, beating hard with the hand. When the mixture is thoroughly beaten (it will take about 20 minutes), spread on buttered sheets in oblong pieces about 4 inches long and 1½ inches wide. Bake in a rather quick oven for about 25 minutes. As soon as they are done, ice with either chocolate or vanilla frosting.
Make an icing with the white of two eggs and ½ cup of powdered sugar. Flavor with 1 teaspoon vanilla extract. Frost the eclairs, and when dry, open on one side, and fill with Custard Filling. Or, they may be filled with cream, sweetened, flavored with vanilla and whipped to a stiff froth. Strawberry and raspberry preserves are sometimes used to fill eclairs.