Brown roast on all sides in hot vegetable oil in a large Dutch oven over medium-high heat; add soup mix, consommé, and thyme sprigs.
Bake, covered, at 325° for 1 hour and 30 minutes. Toss together vegetables, olive oil, and pepper. Add mixture to Dutch oven, and bake 2 hours or until vegetables are tender. Remove roast and vegetables, reserving drippings. Keep warm.
Stir together flour and next 3 ingredients in a large bowl; cut in butter with a pastry blender until crumbly.
Combine egg and milk, whisking until fluffy. Add three-fourths of egg mixture to dry ingredients, stirring until dry ingredients are moistened; add remaining egg mixture, if necessary, to form a soft dough.
Pour reserved drippings through a wire-mesh strainer into a saucepan, discarding solids. Skim off fat. Bring drippings to a boil over medium-high heat; reduce heat to low.
Drop dough by heaping tablespoonfuls into drippings; cover and simmer 10 minutes or until done. Remove and serve with roast and vegetables. Garnish, if desired.