Preheat oven to 350 degrees F.
Grease and flour a 9 inch springform pan.
In a medium sized bowl, sift together the all purpose flour, almond flour, baking powder and salt. Set aside.
In the bowl of a stand mixer or hand held mixer, fitted with the whisk attachment, beat together the eggs and granulated sugar until thick and pale yellow in colour. About 3 minutes.
Mix in the olive oil, milk, vanilla and almond extracts, zest and thyme until well incorporated.
Switch to the paddle attachment and mix in the flour mixture until well combined.
Fold in 1 cup of the grapes with a rubber spatula.
Transfer the cake batter to the prepared pan and level off with the back of a spoon.
Scatter the remaining 1 cup of grapes evenly over the top of the cake.
Sprinkle the top of the cake with sliced almonds.
Bake the cake in a preheated oven for about 40 minutes.
When ready the cake will have a deep golden brown colour and springs back to the touch. Or, if a toothpick inserted inside comes out clean then it's ready.
Remove from the oven and transfer to a cooling rack.
Run a knife alongside the edges of the pan and allow to cool for 30 minutes.
Release the cake from the springform pan and cool completely before dusting with powdered sugar.
Garnish with sugared grapes or fresh thyme leaves if desired. (see notes below on how to make sugared grapes)