Preheat the oven to 350F and lightly butter a 12-hole deep muffin tin.
Roll out the pastry on a lightly floured surface. Using a 4-5in pastry cutter, cut out 12 circles. Loosely press them into the muffin tin, retaining a frilly or wobbly edge to them, rather than pressing in firmly around the edges. Chill in the refrigerator.
In a mixing bowl, beat together the egg yolks, whole eggs and cream and season with salt and pepper. This is your basic mixture, ready to add your chosen flavours.
If you are doing the goat cheese and tomato filling, crumble the goat cheese into the chilled pastry cases and scatter over the basil. Pour over the egg mixture and then top each tart with thin slices of tomato.
If you are doing the ham, cheddar and mustard filling, stir the ham, cheese and mustard into the egg mixture and divide it between the chilled pastry cases.
Place the tarts in the oven for 30-35 minutes until the pastry is lightly golden and the eggs have set. Cool for about 10 minutes before removing from the tin. Serve warm or cold as a savoury afternoon treat.