Preheat oven to 170°C/338°F.
Use a 5-6 cm round cake ring to cut the puff pastry sheet into small circles.
Brush the muffin moulds with oil, arrange 3 round slices of puff pastry in the muffin mould to overlap slightly in the shape of a flower, and press with the tips of your fingers to flatten and seal the puff pastry pieces and make the dough thinner. Place 1-2 teaspoons of custard inside the pastry flower.
Wash the apples but do not remove the skin. Cut the apples into 1cm thick slices with a mandoline or sharp knife.
In a clean saucepan, combine sugar, water, honey and lemon into a saucepan and heat the mixture on the hob at high heat. Glaze the apple slices on both sides for 3-4 minutes until they are soft.
Place 1-2 tablespoons of vanilla custard inside the puff pastry flower base.
Arrange the apple slices on a piece of baking paper to overlap, then roll them into a rose-like shape. Trim the bottom to make the apple pieces even and easier to fit inside the pastry cup and place them inside the pastry base. Sprinkle the apple slices with crystal sugar and cinnamon.
Place the muffin tray with the apple roses in the middle of the hot oven and bake for 20-25 minutes. Keep an eye on the roses while baking and cover them with kitchen foil as soon as the pastry turns golden. When the apple roses are ready, take them out of the oven and let them cool for 20 minutes inside the moulds. Decorate the roses with sifted icing sugar on top.
Serve the mini cakes as a dessert or a snack with a nice cup of tea or coffee.