Caramelized Onion Tart without cookies sprinkles

50 g butter 1 tablespoon olive oil 4 large yellow onions , sliced 1 garlic clove , crushed 2 eggs 2 egg yolks 50 g coarse grain mustard 142 ml double cream[...]

1 tablespoon unsalted butter 2 tablespoons extra virgin olive oil 2 medium onions , thinly sliced 2 tablespoons fresh thyme leaves all-purpose flour , for[...]