Preheat your oven to 350 F. Get a glass (Pyrex) 9x13 pan out.
First, brown the butter. Cut the butter into pieces slices and add to a medium skillet. Heat on medium until it melts , then continue to heat and stir as it starts to foam, then bubble and crackle, and finally quiet down and the bottom will get dark quickly. You want it to be a nice nutty brown but pull before it burns! I have a post on how to brown butter if you need more info. Set aside.
Dice your pears (I don't remove the skin if it's thin and soft), and add to a large bowl. Add the cinnamon, ginger, salt, 3 tablespoons of brown sugar, vanilla, almond extract, and lemon juice, and stir together.
To make the topping, add the browned butter, brown sugar, flour, oats, salt, cinnamon, and cardamom to a medium bowl. Use a fork to stir together so everything is moistened.
Let sit for 10 minutes or so, while you can make the topping. Then add the amaretto and tapioca flour and stir everything together.
Pour the fruit mixture into the baking dish. Use your hands to distribute the topping as evenly as possible.
Bake for 30 to 45 minutes…it will very much depend on the thickness of your filling and topping, but you want the filling to be bubbling up around the sides and the topping to get golden and smell amazing. Let sit for at least 10 minutes (more like 30 is ideal) to let the juices thicken and set.