Pre-heat oven to 350° F. To a high-speed blender or food processor, add first five ingredients. First pulse until mixed, then grind until fine.
Transfer blended mixture to a bowl. In a separate small bowl, stir together maple syrup and oil. Drizzle this over almond mixture and stir with a spoon until it forms somewhat uniform crumbs that will hold together when compressed. Use extra oil if mixture is dry. Reserve 1 cup crumb mixture to use as topping.
Transfer larger amount of crumb mixture to a parchment-lined 8x8-inch baking pan (similar sizes will work as well). Form an even layer of crumb mixture on the bottom of the pan by first pressing down with the back of a spoon. If you want it smoother, place another piece of parchment or waxed paper on top of the base and press this with something that has a hard, flat surface, like a large drinking glass or glass butter dish. Remove top parchment.
Place in pre-heated oven and bake crust for 20 – 25 minutes until the edges have lightly browned and the middle shows some browning.
Remove from oven. Spoon mincemeat onto crust, using the larger quantity if desired. Top with the reserved crumb mixture, spreading it as evenly as possible.
Bake in 350° F oven for 20 – 30 minutes or until the topping is lightly browned. Remove and cool at room temp for one hour. Chill for at least an additional hour before cutting.