Combine almonds, flour, the 1/2 cup of sugar, cinnamon, lemon zest and butter in a food processor. Pulse until just mixed and crumbly. Do not over-process. Pat mixture into pie crust.
Place pear slices in an overlapping pattern over almond mixture.
Sprinkle remaining sugar on top, and bake in the middle of the oven until crust is golden and almond mixture begins to bubble, about 30-35 minutes.
Remove from oven, carefully brush with Lemon Pear Marmalade, and place remaining almonds around outside of fruit.
Let pie stand for about 10 minutes, then cut into slices and serve.