Depressurize cooker using the quick-release method, then carefully remove lid, allowing steam to escape away from you. Strain broth through fine-mesh strainer into clean heatproof container, pressing on solids to extract as much liquid as possible; add water as needed to yield a total 3 cups (700ml) broth. Season with additional salt to taste. Transfer lamb to cutting board and set broth aside to cool to room temperature. When broth has cooled, cover and refrigerate until ready to use. When lamb is cool enough to handle, separate meat from bones in large pieces; set meat aside and discard bones. For the Dough: Place flour and salt in food processor bowl and pulse twice to combine. Add butter and process until fully incorporated, 10 to 20 seconds. Add water (adding extra 1 teaspoon (5ml) water if rolling dough by hand) and egg yolk and process until dough ball starts to form and mixture looks pebbly, about 30 seconds. Transfer dough to lightly floured counter; return food processor bowl to base, but don’t clean it. Knead dough until uniform in texture (dough will remain slightly rough in texture), 15 to 30 seconds. Form dough into a 4-inch disk, wrap tightly in plastic, and set aside to rest on countertop for at least 30 minutes and up to 2 hours (or transfer to refrigerator for up to 24 hours). For the Manti Filling: Meanwhile, in now-empty food processor, place onion, garlic, parsley, paprika, allspice, Aleppo pepper, salt, and pepper and process until smooth, scraping down sides of bowl as needed, about 15 seconds.
