Place brisket in a 9×13-inch pan. Add sauces, salt, and pepper. Cover tightly and bake at 275 degrees Fahrenheit for three hours.

Remove pan from the oven and let the meat rest 15 minutes. Using two forks, shred the meat. Use kitchen shears, if needed, to cut long strands into smaller pieces. Set aside brisket and all the sauce in the pan. The meat should reabsorb most of the liquid.

Preheat oven to 350 degrees Fahrenheit. Line a sheet pan with a silicone mat.

In a large bowl, whisk all ingredients to combine. Mix until creamy and no lumps of starch remain.

Use an offset spatula to spread the batter onto the mat.

Bake for 10 minutes; remove from oven and use a pizza cutter to cut the kichel. Make one long cut down the center of the length of the pan. Then make five equally-spaced cuts across the width, resulting in twelve three-by-six-inch rectangular crackers. Bake another 15 to 25 minutes. Remove from oven and cool.

Top each cracker with sauteed onion or smashed roasted garlic. Add pulled beef. Drizzle with horseradish mayonnaise. Serve warm or room temperature.