1/4 cup maple syrup

Make the oatmeal: Arrange a rack in the middle of the oven and heat to 350 F. Coat a broiler-safe 9-by-9-inch baking dish with butter; set aside.

Combine the oats, baking powder and salt in a medium bowl; set aside. Beat the egg whites in a large bowl with an electric mixer until firm peaks form; set aside.

Whisk the cookie butter in a large bowl to soften and separate. Add the milk, heavy cream, vanilla, ginger and lemon zest, and whisk to combine. Mix in the oat mixture until thoroughly combined. Gently fold in the egg whites and 1 cup of raspberries.

Transfer to the prepared dish and gently smooth over with a spatula. Bake until the center is just set and the top is lightly browned, 10 to 15 minutes. Meanwhile, make the crumble.

Make the crumble: Whisk the oatmeal, flour, ginger, cinnamon and salt together in a medium bowl. Add the cubed butter and work it in with your fingers until it resembles coarse crumbs. Add the pistachios and stir in the maple syrup.

When the oatmeal is ready, remove it from the oven. Sprinkle the crumble over the baked oatmeal, then bake for 5 to 8 minutes more. Turn the oven on to broil, and broil until the crumble is deep golden-brown, about 5 minutes. Top with additional fresh raspberries before serving.

Recipe note: Leftovers can be stored in an airtight container in the refrigerator for up to five days.

(Jenny Huang is a contributor to TheKitchn.com, a nationally known blog for people who love food and home cooking. Submit any comments or questions to editorial@thekitchn.com.)