Preheat oven to 425°F (220 C). Sprinkle large rimmed baking sheet with flour. Whisk first 3 ingredients in large bowl. Stir in chives and cheese. Whisk 3/4 cup milk, 1 egg, oil, and mustard in small bowl. Gradually add milk mixture to dry ingredients, tossing until moist clumps form and adding more milk by tablespoonfuls if dough is dry. Turn dough out onto lightly floured surface; knead just until dough comes together.
Pat out dough to 1-inch-thick round. Using 2 1/2-inch-diameter cutter, cut out scones. Gather dough scraps and repeat. Transfer to prepared sheet. Whisk remaining egg in small cup; brush over scones. Sprinkle with sesame seeds.
Bake scones until golden on top and tester inserted into center comes out clean, about 14 minutes. Cool scones on sheet 5 minutes. Transfer to basket. Serve warm.
Makes about 14 scones.
Source: Bon Appétit May 2004
Date: June 25, 2004