Preheat the oven to 350°F and spritz a 3 quart casserole with cooking spray.
Toss the fresh pineapple chunks with the juice of one lemon, 3 Tbsp brown sugar, 2 Tbsp all-purpose flour and 1/4 tsp ground ginger. Pour into the dish.
Sift together the all-purpose flour, oats, brown sugar and granulated sugar for the topping.
Cut cubed butter into the dry ingredients until it resembles coarse crumbs. Mix-in the sweetened coconut and nuts by hand. Sprinkle on top of the pineapple.
Bake for 30 minutes or until the topping is golden and the edge is bubbly.
Serve with a drizzle of warm caramel and a scoop of vanilla ice cream, if desired.