Ramps and Buttermilk Biscuits With Cracked Coriander

Preheat oven to 425°F. Mix buttermilk and ramps in small bowl. Mix flour, baking powder, salt, and pepper in processor. Add chilled butter to processor; using on/off turns, cut in butter until fine meal forms. Transfer flour mixture to medium bowl. Add buttermilk mixture; stir until dough forms. Turn dough out onto lightly floured work surface and press out to 7-inch round, about 1/2 inch thick. Using 2-inch-diameter biscuit cutter dipped in flour, cut out rounds. Gather dough scraps; press out to 1/2-inch thickness and cut out additional rounds. Transfer dough rounds to baking sheet. Brush biscuit tops with some of egg glaze. Sprinkle with cracked coriander seeds. Bake biscuits until golden brown, about 20 minutes. Cool on rack. Serve slightly warm or at room temperature.