Toss pears with 1 tablespoon sugar and 1/4 teaspoon of the shredded lemon peel in a 2-quart square baking dish.
For topping, in a bowl combine oats, brown sugar, flour, cardamom, and 1/4 teaspoon more lemon peel. Cut in the 1/4 cup butter or margarine until mixture resembles coarse crumbs. Stir in almonds. Sprinkle topping over fruit.
Bake in the preheated oven for 30 to 35 minutes or until fruit is tender and topping begins to brown.
Meanwhile, stir together 1/4 cup sugar and cornstarch in a 1-quart saucepan. Add water; stir until combined. Cook and stir over medium heat until thickened and bubbly. Cook and stir 2 minutes more. Remove saucepan from heat. Beat egg yolk in a small bowl. Stir in little of the hot mixture into beaten egg yolk. Return all of the mixture to the saucepan. Cook and stir over low heat until nearly bubbly. Cook and stir 1 minute more. Remove from heat. Stir in 1 tablespoon butter or margarine, the remaining teaspoon lemon peel, and lemon juice. Serve sauce warm over crisp. Makes 6 servings.