Preheat oven to 350F. Line an 8-inch cake pan with parchment paper; this is very important! Use a pastry brush and spread butter over the parchment paper.

In a small bowl, combine the brown sugar, cinnamon, nutmeg and cornstarch; set aside. Arrange sliced fruit on the bottom of the pan, over-lapping the fruit slightly and in the center. Sprinkle with prepared sugar mixture and slivered almonds; set aside.

Place eggs, white granulated sugar and vanilla extract into mixer bowl. Whisk on high speed until eggs are thick, pale and fluffy. Gently fold in the sour cream. Combine the flour and baking powder and sift into the batter in small batches, folding it in gently after each addition. Fold in diced strawberries.

Pour batter over prepared fruit in pan. Bake in preheated oven until top is golden brown, about 25 minutes. Remove cake from oven when done and let stand for about 30 minutes.

Run a knife along the edge of the edge of the pan to release the cake. Turn cake over onto cake platter and tap the pan a few times. Lift off the pan and peel away the parchment paper. Serve upside down cake warm; store in refrigerator when not serving. Reheat in microwave or in warm oven.