Preheat oven to 350 degrees F. In a large mixing bowl place cheese, butter, flour, 1/4 teaspoon salt, and pepper; let stand for 30 minutes at room temperature. Beat with an electric mixer on medium speed until combined. Using your hands, work dough until it holds together. Divide dough in half.

Line two 8x8x2-inch baking pans or 2-quart square baking dishes with plastic wrap. Press half the dough evenly into each prepared pan. Cover and chill about 30 minutes. Invert one pan onto a very large (17x13-inch) ungreased baking sheet. Lift pan and carefully peel off plastic wrap. Using a floured knife cut dough into eight 1-inch-wide strips. Cut strips crosswise into four 2-inch-long rectangles to make 32 (2x1-inch) rectangles (do not separate rectangles). Repeat on the same baking sheet with remaining dough. With a floured fork, prick each rectangle 2 or 3 times. Sprinkle very lightly with sea salt.

Bake for 20 to 25 minutes or until light brown. Cut through the rectangles again while shortbread is still warm. Transfer to a wire rack and cool. Use immediately or store in an airtight container in the refrigerator up to 2 days or in the freezer up to 3 months.

To serve White Cheddar Shortbread Sandwiches, top half the crackers with about 1 teaspoon of the Red Onion Marmalade. Top with remaining crackers. If desired, top with additional marmalade. Makes 32 sandwiches.

To make in a food processor, combine the cheese, butter (cut up), flour, 1/4 tsp. salt, and pepper in a food processor bowl. Let stand at room temperature for 30 minutes. Cover and process until mixture holds together. Continue as above.

In a medium saucepan combine the 2 large red onions chopped (4 cups), 1 cup packed brown sugar, 1 cup red wine vinegar, 2 tsp., snipped fresh thyme or 1/2 teaspoon dried thyme crushed, if using, and 1 tsp. bottled minced garlic or 4 cloves garlic minced. Bring to boiling over medium heat; reduce heat. Simmer, uncovered, about 45 minutes until onions are tender and liquid is nearly evaporated. (Mixture will thicken more as it cools.) Stir in fresh thyme, if using; remove from heat and allow to cool. Use immediately or store, tightly covered, in refrigerator up to 2 weeks.