Thaw onions in a colander under cool water.Melt butter in a medium sauce pan over medium high heat and add the onions. Cook for 2 minutes.Add the peas and cook for 3 more minutes. Add the wine and reduce for 2 minutes.Add he stock and cover the pan with a lid and cook for 6 minutes, until peas are firm, but tender.Mix the cream with the flour in a small bowl or measuring cup.Remove the pan from the heat and add the cream mixture. Stir. Add the thyme, salt and red pepper flakes.Put the pan back on the heat on medium low. Cook for another 3 minutes until it's the consistency you like; it should be creamy and thick.Add the lemon juice and stir.Serve warm with fresh chopped parsley.