Place the pecan pieces and flax seeds in the bowl of a food processor fitted with the blade attachment. Process until coarsely ground, about 5 seconds. Transfer to a small bowl, and stir in the cane syrup until coated.
Slice the bananas into coins and drizzle with the lemon juice. Gently turn to coat - this will help prevent browning.
Spoon 1/3 cup of yogurt each into the bottom of 4 (8-ounce) cups, then 2 Tbsp. of the pecan mixture, and a few banana slices. Repeat your layers, finishing with the final 1/3 cup of yogurt.
Sprinkle the top of each cup with pecan pieces and serve immediately, or seal with plastic wrap and refrigerate for up to 1 day.
