Prepare flax egg by mixing flaxseed meal and water in a small bowl. Set aside.
Beat peanut butter and softened butter together until light and fluffy. Add flax egg, brown sugar and stir.
Add graham crumbs and stir to combine. Then add in flour a little bit at a time until a firm dough forms - you don't want it to be crumbly. It should take about 1/2 cup (as original recipe is written).
Scoop out 1 packed Tbsp worth of dough and gently form/roll into balls. Moisten your hands with olive or canola oil if they aren't molding easily. Place on lightly greased baking sheet.
Flatten balls gently with the bottom of a glass and use your thumb or finger to make an indention.
Bake for 8 minutes and remove from oven. The indentions should've puffed up, so press them back down a little and pop them back in the oven to brown up a little more - 2-3 minutes until slightly golden brown. Be careful not to over-bake or they'll be too crunchy.
Let rest on pans for a few minutes then transfer to cool on wire racks. Once the cookies are cooled, heat your jam until warm and pourable in a saucepan over medium-low heat or in the microwave. Then spoon small amounts (~1 tsp) of your jam into the middle of each cookie. Sprinkle with a few more graham cracker crumbs and serve immediately.
Let cool completely before covering. To store, cover and keep at room temperature for up to 2-3 days.