Wash leeks well and pat dry. Slice crosswise into rings about 1/4″ wide. Separate rings.
Heat 1/2 inch oil until shimmering. Add all but 1/2 cup of leeks and cook over moderate heat until golden brown – about 10-12 minutes. Drain on paper towels.
Season leeks with salt and pepper.
In large skillet cook bacon until golden. Drain and crumble.
Add remaining leeks and thyme to bacon fat and cook until leeks have softened – about 8 mins.
Add half the stock and cook until reduced by half. Add heavy cream and cook until reduced by half. Stir in peas, bacon and remaining stock and bring to boil – discard thyme.
Season with salt and pepper. Stir in cornstarch and water and cook until slightly thickened.
Transfer to bowl and top with crispy leeks just before serving.
