Pour the milk in a bowl, sprinkle the gelatin powder over and set aside for 5 minutes. Then, pop into the microwave for 90 seconds, stirring at every 30 second intervals ensuring it has dissolved well.
In a saucepan, pour in the heavy cream and sugar over medium heat. Bring to a boil, all the while stirring continuously. Gently pour in the milk and gelatin mix, and cook for a minute until fully dissolved.
Take off heat, pour in only 1/2 cup of the peach liqueur and vanilla extract, give it one last stir and pour into a glass bowl. Once cooled at room temperature, cover with a plastic wrap and refrigerate for 6 hours before serving.
Meanwhile, drain the sliced canned peaches, reserving only 1/4 of the liquid. Mix this with the remaining 1/4 cup of peach liqueur and let this sit refrigerated until the panna cotta is ready.
Just before serving, spoon over the sliced canned peaches and stuff your face.