Preheat oven to 400 degrees. In a bowl, gently stir together pears, lemon juice, cranberries, sugar, and flour until combined. Divide mixture evenly into 4 8-ounce ramekins on a sheet pan. !To Make the Topping: In a food processor, pulse the flour and butter until clumps form. Add the sugar, brown sugar, cinnamon, oats, and salt. Pulse a few times until mixture is crumbly. Sprinkle each ramekin generously with the topping mixture. Bake until fruit is tender and topping is browned, about 25-30 minutes. Serve warm with vanilla ice cream on top.