In a small saucepan, combine diced peaches, sugar, lemon zest and lemon juice. Cook over medium heat. Once boiling, continue to reduce for 15 minutes, stirring occasionally. Break the peaches into small pieces with a spatula. Remove from heat and set aside to cool completely.
For the crumble, in a medium bowl, combine flour, sugar, butter, cinnamon and salt. Rub together with your fingertips until the mixture resembles breadcrumbs. Transfer to the fridge and chill for 15 minutes.
Preheat the oven to 350˚F (180˚C). Line a baking sheet with a parchment paper.
When ready to bake, spread the mixture onto the center of the baking sheet. Bake in the oven until golden brown, about 13 - 15 minutes.
Transfer the baking sheet to a cooling rack. Cool completely. Break into small pieces with your fingers.
When the jam and crumbles are cool, get the cream mixture ready. In a microwave-safe measuring cup or bowl, add milk. Microwave for 30 seconds or until warm. Add condensed milk and stir to blend. Stir in heavy cream.
Get the popsicle mold or small paper cups ready, the filling will divide into 2 parts. The 1st round will be filled about half way in the mold. Start by little bit of cream mixture, then ½ teaspoon of jam (each), little bit of crumbles, ½ teaspoon of jam and add enough cream until about ½ way through the mold. Transfer to the freezer and freeze for about 1 hour. Cover the cream and jam with plastic wraps and keep in the fridge.
Now 2nd round, add ½ teaspoon of jam, little crumbles, cream mixture, and then more jam, crumbles. Most the jam should be used at this point. If not, add a little more jam into the mold. Fill the mold with cream mixture by leaving ⅛-inch space on top. If using mold that contain sticks, put on lid, sticks and freeze. If using small cups, freeze until beginning to set, about 40 minutes, then insert wooden sticks and put back in freezer.
Keep the leftover crumbles in an airtight container. They will be used again.
Freeze for at least 8 hours or overnight. If the popsicles are stuck in the molds, dip the molds in warm water for 10 seconds or so. Sprinkle a little bit more crumbles on top and serve. If not serving right away, place the popsicles on a large plate or small baking sheet that is covered with a parchment paper. Cover the popsicles with another parchment paper. Put back in the freezer to refreeze for a couple more hours.