Streusel: combine brown sugar and granulated sugar in a small bowl. Add flour and mix to combine. Add butter and work in with fingertips until mixture resembles coarse crumbs. Refrigerate in airtight container until ready to use.
Galette: preheat oven to 400. Cut pineapple slices in half and place on paper towel to absorb juice. Arrange pineapple slices over pastry in concentric circles, overlapping them slightly, leaving 3 cm border around edge. Fold pastry edge over edges of pineapple slices all around the galette. Sprinkle streusel over top. Bake 40-45 minutes or until crust is golden brown. Remove from oven and brush warm apricot glaze over pineapple slices and serve lukewarm cut into slices. *A store bought pie shell works fine for this recipe or make your own pastry with flour and butter ( 2 cups flour to 1 stick of butter). Use ice water until it make a pastry ball.