Trim excess fat from meat; cut into 1-inch (2.5 cm) cubes. In large bowl, combine
2 tablespoons (25 mL) flour, paprika, salt and pepper; add meat and toss to coat.
In large heavy saucepan or Dutch oven, melt half of the butter over medium-high heat; brown beef, in batches and adding more butter if necessary. Remove meat and set aside.
Add remaining butter to pan; cook onions and garlic; stirring and adding 1 tablespoon (15 mL) water if pan is browning too much, for 5 minutes or until softened. Stir in carrots, celery leaves, parsley, thyme and bay leaf; stir in 1/3 cup (75 mL) flour.
Return meat to pan; pour in beer. Add sugar; bring to boil. Reduce heat to low; cover and simmer for 1 1/2 hours. Uncover and simmer for 1 1/2 hours longer or until meat is tender and sauce is slightly thickened.
Stir in vinegar; simmer, uncovered, for 10 minutes. Remove bay leaf. (Make-ahead: Stew can be cooled, covered and refrigerated for up to 3 days; reheat over medium-low heat for about 45 minutes.) Garnish with finely chopped parsley.