Heat the oil in a large pot over medium-high heat and add the tempeh. Cook, stirring frequently, for about 10 minutes, or until it's golden brown.
Pour the tamari onto the tempeh, and continue cooking stirring frequently, until all the liquid absorbs, about 2 or 3 minutes.
Add leeks, mushrooms, and garlic to pot and sauté for 5 minutes, or until the mushrooms and leeks begin to soften.
Sprinkle in the flour and cook 1 more minute, stirring frequently.
Add the stock, wine, thyme, and dried parsley, and bring the mixture to a boil.
Reduce the heat and simmer 15 minutes.
Stir in the lemon juice, salt and pepper.
Remove from the heat and garnish with fresh parsley.