Preheat oven to 400 degrees. In a food processor, pulse almonds, sugar, flour, and salt until finely ground. Add egg, vanilla, and nutmeg and process until combined.
Lay 1 sheet phyllo on a parchment-lined rimmed baking sheet, lightly brush with butter, and sprinkle with about 1/2 teaspoon sugar. (Keep extra phyllo covered while you work.) Stack remaining 5 sheets phyllo on top, brushing each with butter and sprinkling with sugar (omit sugar on last layer). Trim stack into an 11-by-15-inch rectangle. Spread almond mixture evenly on stack, leaving a 1-inch border. Arrange pears on top, overlapping slightly.
Bake until edges are golden and fruit is tender, about 18 minutes, rotating sheet halfway through. Let tart cool slightly on sheet on a wire rack. Serve warm or at room temperature.
Be gentle when spreading the almond mixture, as phyllo tears easily. Dollop mixture on phyllo and use an offset spatula or a spoon -- instead of a knife -- to avoid trouble.