Place meat in a large plastic bag. Combine 1/4 cup flour with salt in a small bowl; pour into the bag and shake to coat meat.

Heat olive oil in a large skillet over medium-high heat. Add floured meat and cook in batches, if necessary, until evenly browned on the outside. Transfer meat to a slow cooker.

Melt butter in the same skillet. Add onions and sauté until softened. Transfer to the slow cooker. Pour red wine into the skillet and stir to loosen any browned bits of food on the bottom. Remove from heat and pour into the slow cooker.

Add potatoes, carrots, parsley, and pepper to the slow cooker. Stir 2 cups boiling water and dry soup mix together in a small bowl; pour into the slow cooker.

Cover and cook on High for 30 minutes. Reduce heat to Low and cook until meat is fork-tender, about 6 hours. Mix 1/4 cup warm water and 2 tablespoons flour together in a small bowl until smooth; stir into stew and cook, uncovered, until thickened, about 15 minutes.