Place the flour and sugar in the bowl of stand mixer (Kitchenaïd here). The dough can be kneaded by hand for about fifteen minutes until it forms a soft, smooth ball.

In a saucepan, combine the milk and water and gently heat until slightly warm.

Pour over flour and start kneading on speed 2. Knead the dough for about 12 minutes, until it pulls away from the sides of the bowl and forms a ball around the dough hook.

Add the dry yeast while continuing to knead, then gradually incorporate the softened butter.

When the butter is well incorporated into the dough, add the egg and salt.

Knead until the dough pulls away from the sides and is soft and smooth (you can watch the steps on the video).

Turn the dough out onto the work surface and knead just until smooth, then shape into a ball.

Place the dough in a bowl. You can return it to the mixer bowl if you don't need it.

Cover the bowl with cling film and a towel. Leave to double in volume for 1 to 1.5 hours in a warm, draught-free place.

When the dough has risen, punch it down to deflate it.

Turn it out onto the work surface and divide it into small portions of 20g (0.7 oz) each, about the size of a large walnut

Shape each portion into a smooth ball.

Place the balls onto a baking tray lined with parchment paper. Cover with a towel and leave to rise for 1 hour at room temperature. The balls will slightly puff up.

Preheat the oven to 210°C (410°F) at the end of the rising time.

Dilute 2 egg yolks with 2 teaspoons of water, milk, or cream, and gently brush the mixture onto the dough balls using a pastry brush.

Sprinkle with sesame or poppy seeds.

Bake for about 12 minutes, depending on your oven, until the buns are golden brown.

Remove the buns from the oven, place them on a wire rack and cover with a towel to retain moisture and prevent them from drying out. They'll stay soft that way.

In a bowl, mix the meat with a pinch of salt, a bit of pepper, and the egg.

Form small balls of 20g (0.7 oz) each.

Flatten each patty to be slightly larger than the mini buns. The patty will shrink slightly while cooking.

Heat a little oil in a frying pan and cook the patties on both sides.

Cut the mini burger buns in half and spread ketchup on the bottom half. Place a little caramelized onion confit on top.

Cut each slice of cheese into 4 small squares and place them on top of the caramelized onions. You can place the beef patty first, followed by the cheese, or vice versa; it's up to your preference.

Cover with a piece of lettuce and then place the beef patty on top. Top with a little ketchup.

Put the top of the mini burgers back on and secure everything with a cocktail pick at the center.

You can reheat them for about ten minutes at 120°C (250°F) before serving.

If you have prepared them a few hours before serving, wrap with cling film and store in the fridge.