Soak the gelatine in a container with cold water and leave it aside.
Prepare the base: finely chop the biscuits, mix them with the melted butter and create the base in the mold lined with parchment paper. Refrigerate for 30 minutes.
Prepare the filling: whip together the cheese, yogurt and sugar. Now squeeze the gelatine, dissolve it with 1-2 tablespoons of hot cream and add it to the cheeses.
Whip the cold cream from the fridge, add it to the cream cheese and mix gently with a spatula.
Take the mold out of the fridge, pour in 3/4 of the filling (put the rest aside) and level. Put in the fridge.
Meanwhile, prepare the watermelon jelly: remove the seeds from the watermelon, then blend it, strain it and transfer it to a saucepan. Add the sugar, bring to a boil, then remove from the heat, add the squeezed gelatine and stir until it dissolves completely. Let it cool to room temperature (it will take 1 hour).
Take back the mold, add the watermelon jelly now at room temperature (it should be semi-liquid) and put the cheesecake in the freezer for at least 2 hours.
Take back the mold and decorate with the chocolate chips, placing them a little scattered, so that they look like seeds. Remove the outer circle of the springform pan.
Transfer the cake to a serving dish, add the coloring in the stuffing set aside, mix and glaze the edges of the cheesecake, for the entire height, so as to simulate the skin of the watermelon.
Your watermelon cheesecake is ready, bring it to the table and serve it immediately.