Preheat oven to 400'F. (205'C.). Sift flour, salt and spices into a bowl. Cut in butter finely until mixture resembles breadcrumbs. Add grated cheese and mix well. Mix egg with cold water. Add 2 tablespoons of egg mixture to cheese mixture and mix to form a fairly stiff dough. Knead gently on a lightly floured surface. Roll out dough to a 12x6" rectangle. Trim edges. Cut in half lengthwise and transfer to a baking sheet. Brush each half with remaining egg mixture. Sprinkle 1 half with sesame seeds and the other half with poppy seeds. Cut each half in 10 triangles and separate slightly to prevent sticking. Bake in preheated oven 10-12 minutes or until light golden and cooked through. Cool on a wire rack. Store in an airtight container up to 2 weeks.