1. Trim lamb and cut into 1-inch (2.5 cm) cubes. In large skillet, heat oil over medium-high heat; brown lamb, in batches. Transfer to slow cooker.
2. Drain fat from skillet. Fry onions, garlic, mint, salt and pepper over medium heat, stirring occasionally, until onions are softened, about 5 minutes. Scrape into slow cooker.
3. Add half the broth to skillet; bring to boil, scraping up brown bits from bottom of skillet. Scrape into slow cooker along with remaining broth, squash, chickpeas and tomato paste. Stir to combine.
4. Cover and cook on low until lamb is tender, about 6 to 8 hours. Skim off fat. Move meat and vegetables to 1 side of slow cooker.
5. Whisk flour with ¼ cup (50 mL) of water; whisk into liquid in slow cooker. Stir to redistribute ingredients.
6. Cover and cook on high until thickened, about 15 minutes. (Make-ahead: Let cool for 30 minutes. Refrigerate, uncovered, in airtight containers until cold. Cover and refrigerate for up to 3 days or freeze for up to 1 month.)
7. Stir in parsley, lemon juice and hot pepper sauce.