Preparation Bring milk, cloves, and bay leaf to a boil in a small saucepan; reduce heat to low and simmer for 15 minutes to let flavors meld. Strain into a medium bowl; discard solids. Cover milk and keep warm. Meanwhile, place onions in a large skillet (at least 12"). Add water to half-cover the onions (about 1 cup). Add 1 tablespoon butter, 1 teaspoon salt, and sugar. Cook over medium-high heat, stirring occasionally, until liquid has evaporated and onions are golden brown, about 12 minutes. Gently transfer onions to a large plate. Melt remaining 2 tablespoons butter in same skillet over medium heat; add flour and whisk to combine. Cook, stirring occasionally and scraping up browned bits from bottom of pan, for 1 minute. Whisk in reserved milk, adding 1/4-cupful at a time. Cook, stirring constantly, until thickened and bubbly. Stir in remaining 1/2 teaspoon salt, pepper, and nutmeg. Add peas and onions; stir until heated through. Gently fold in crème fraîche.
Preparation Bring milk, cloves, and bay leaf to a boil in a small saucepan; reduce heat to low and simmer for 15 minutes to let flavors meld. Strain into a medium bowl; discard solids. Cover milk and keep warm. Meanwhile, place onions in a large skillet (at least 12"). Add water to half-cover the onions (about 1 cup). Add 1 tablespoon butter, 1 teaspoon salt, and sugar. Cook over medium-high heat, stirring occasionally, until liquid has evaporated and onions are golden brown, about 12 minutes. Gently transfer onions to a large plate. Melt remaining 2 tablespoons butter in same skillet over medium heat; add flour and whisk to combine. Cook, stirring occasionally and scraping up browned bits from bottom of pan, for 1 minute. Whisk in reserved milk, adding 1/4-cupful at a time. Cook, stirring constantly, until thickened and bubbly. Stir in remaining 1/2 teaspoon salt, pepper, and nutmeg. Add peas and onions; stir until heated through. Gently fold in crème fraîche.