Taleggio tart with walnut pastry

Name: Taleggio tart with walnut pastry
Ingredients: 200g plain flour, plus extra for dusting; 50g walnuts (shelled weight); 50g cold butter, chopped into small pieces; 25g vegetarian hard cheese (or Parmesan if you’re not making a strictly vegetarian version), grated; 1 medium egg, beaten; 1 tbsp olive oil; 6 shallots, sliced; 3 large garlic cloves, finely chopped; 1 whole egg and 2 egg yolks; 200ml double cream; 140g vegetarian Taleggio, rind removed, cut into 1cm/1/2in chunks; 1 punnet cress; zest 1 lemon, plus extra to serve