I found this recipe in one of my favorite books of all time, “An Embarrassment of Mangoes” by Ann Vanderhoof. This book transported me to the Caribbean in the middle of one of those Minnesota winters you’re pretty sure will never end. I’ve made this recipe at least 50 times (and a couple times for a crowd when I was a chef at a tearoom). It’s tried and true 
Just make sure you’re mangoes are ripe. The following excerpt is written by Ann Vanderhoof :
Mango Crisp
For Topping:
1/2 cup flour
3/4 cup quick-cooking or old-fashioned oats
2/3 cup packed brown sugar
1/4 tsp freshly grated nutmeg
2 tbsp finely chopped crystallized ginger
1/3 cup cold butter
For Fruit:
6 cups sliced ripe mango (about 3 – 4 mangoes, depending on size)
1 1/2 tbsp freshly squeezed lime juice
1/4 cup packed brown sugar (approx)
2 tbsp flour
1. Preheat oven to 350 F. Butter a 2-quart (8-inch-square) baking dish
2. Prepare the topping: In a large bowl, combine flour, oats, brown sugar, nutmeg, and crystallized ginger. Cut in cold butter until mixture resembles coarse crumbs. Set aside
3. Toss the mango with the lime juice. Combine sugar and flour, and toss with fruit. Taste and adjust sweetness if desired. Spread fruit in the prepared dish
4. Sprinkle topping evenly over fruit. Bake in preheated oven for about 40 – 50 minutes, until the fruit is bubbling and the topping is crisp and lightly browned. Serve warm
Tips:
For a nutty topping, toss about 1/2 cup slivered almonds with the topping mixture
To make crème fraîche, combine 2 cups whipping cream and 1 cup sour cream in a nonmetallic bow, cover with plastic, and let stand at room temperature for 16 – 24 hours or until thickened. Refrigerate until serving
To make your own crystallized ginger, peel ginger, slice into 1/4 inch thick slices, and boil in cane syrup or sugar syrup for 20 minutes. Remove from syrup, drain, and roll in granulated sugar. Allow to air dry on a rack, then keep in a tightly closed jar