I'm a big tart (maker). I love these recipes - all savoury. My son is v fussy - he has eaten them in the past and I hope he might again:
Richard Bertinet's chicken and tarragon tart - you make semolina pastry, then a kind of roux for the filling, using 100g butter, 100g flour, 1 litre milk and 4 egg yolks. Into that, you grate 50g emmenthal, 30g parmesan, 2tsp Dijon mustard, seasoning and grated nutmeg, 500g cooked chicken, cut into strips, button mushrooms, chopped tarragon and parsley, then bake for 20-25 mins. You could leave out the tarragon and swap the cheese for cheddar if it makes it more child-friendly.
Maxine Clark's sausage, sun-dried tomato and potato tart: Blind bake pastry, then for the filling, heat some oil in a saucepan and add 3 finely slice onions and two cloves chopped garlic and 3tbsp water and cook over a low heat until they are soft but not coloured (add more water if necessary). Blanch 200g potatoes in boiling water for one minute, then chop into small cubes. Heat oil in a non-stick frying pan and add 350g sausage meat (or sausages removed from their skins)- break it up with a fork as you cook. After 5 mins, stir in 1tbsp plain flour, 2-3tbsp tomato puree, 12 sundried tomatoes, chopped, 1tsp dried chilli flakes, 2tsp herbes de provence and seasoning, then stir in the potatoes. Spoon all this into the pastry case, dot over 150g mascarpone cheese, cover with the onions and bake for 25 mins until the onions are golden.
Annie Bell's pea and feta tart and spinach and gruyere tart are both also really lovely and pretty easy - it was Annie Bell who really got me into tart making years ago. They're both in her book Gorgeous Greens!