Place a rack in the center of the oven and preheat oven to 350 degrees F. Take out an 8×8-inch baking dish and set aside.
First prepare the filling. Cut the top stem and bottom butt off of each pear. The bottom will give you a stable base to peel the pears. Use a small paring knife to peel the pears. Slice each pear in half. Use a small teaspoon to gently run down the length of the inside of the pear, removing the fiberous inside spine, and then scooping out the seeds. Dice the pears into hearty bite-size chunks and place in baking dish. Pour cranberries into dish. Top with sugar, cinnamon, and lemon juice. Toss lightly and set aside.
Next prepare the topping. Whisk together flour, brown sugar, raw sugar, cinnamon, nutmeg, salt, and oats. Add unsalted butter and incorporate with your fingers. Work the butter into the topping mixture until it is well incorporated and some butter bits are still the size of oat flakes or small peas. Add about 1/3 of the topping mixture to the pear and cranberry mixture. Toss to incorporate. Place the remaining topping on top of the mixture.
Bake for 40-45 minutes, until bubbly and delicious smelling.
Remove from oven and allow to cool for about 20 minutes before serving. This dish is perfect served warm with vanilla ice cream.
Crumble lasts for up to 3 days, covered, in the fridge.