Preheat oven to 200°C (400°F). Peel and finely chop the shallots. To a large frying pan on low to medium heat, add 2 tbsp of butter until melted. Add the shallots and 2 cloves of grated garlic. Gently sweat until translucent leave to cool.
Place the mince, bread crumbs, egg, lemon zest, tarragon, the shallot mixture that’s cooled down, (1½ tsp) salt, a generous amount of pepper in a bowl and mix to combine. Weigh the total amount then divide by 8. Make each ball that weight so they are all the same size and you get exactly 8. (Approx. 4 ¼oz or 125g) Take approx 2 heaped tablespoons of the mixture and form into balls and set aside. I also like to coat them in olive oil but that’s optional.
To make the leek and tarragon sauce, heat a large ovenproof frying pan over medium heat.
Add the oil and finely chopped white of leek and cook for 6 minutes or until golden. You want only a few bits of brown.
Pour in the wine and cook for 2 minutes. Add the stock, mustard, cream and tarragon. Increase the heat to a simmer and cook for 5-8 minutes. Add the meatballs and gently stir to coat.
Transfer the pan to oven and bake for 15-20 minutes or until golden and cooked through. Brush on olive oil and serve with the sauce immediately. Garnish with fresh tarragon or chopped parsley if you don’t have it.