In 4½- to 5-quart Dutch oven, heat oil over medium-high heat.
Add onions and celery; cook, stirring frequently, until tender.
Stir in remaining stew ingredients.
Heat to boiling.
Reduce heat to low; simmer uncovered 15 to 20 minutes or until beans are tender.
Meanwhile, in medium bowl, mix flour, baking powder, salt and mustard.
Cut in butter, using pastry blender or fork, until mixture looks like coarse crumbs.
Stir in cheese.
Add milk; stir just until dry ingredients are moistened.
Drop dough by rounded tablespoonfuls onto simmering stew.
Cover; cook over medium-low heat 20 to 25 minutes or until dumplings are firm when pressed.
Notes / Tips / Wine Advice:
Resist the urge to stir too much! Dumplings require very little mixing when the milk is added to the dry ingredients. If the dough is overmixed, the dumplings can become heavy and tough, so mix just until the dry ingredients are moistened.