Sift flour, baking powder, baking soda and salt together. Set aside.
Whisk eggs with a wire whisk for about 1 minute. They will become frothy and lightened in color. Add oil and whisk until combined.
Add sugar and whisk for about 1 minute. You can use a mixer to do this, or simply a whisk. I usually go with just a whisk.
Add vanilla extract.
Add half of the flour, whisk briefly until just combined.
Now, add half of the buttermilk, and whisk until incorporated.
Add the other half of the dry ingredients and whisk gently.
Finally, add rest of the buttermilk. Make sure to just whisk the mixture until combined.
Don’t overmix it!
Pour batter evenly into a cupcake pan lined with cupcake liners, or buttered and floured.
Bake for 10-12 minutes, checking in between to rotate pans.
Remove from the oven once cupcakes are lightly golden brown and puffed.
Grape Jam
Mixe grapes, sugar, and lemon juice in a small saucepan.
Bring it to a boil, then reduce the heat to medium low, and cook for about 30 minutes, stirring constantly until a thermometer reads 220F. Once that happens, the jam will be very thick and reduced, you remove it from the heat.
Let it cool down for about 5 minutes. Transfer it to the bowl of a small food processor or blender. Puree jam until smooth.
Let it cool completely in the fridge before using it.
If, for some reason, your jam is too liquidy, and not becoming thick and reduced enough, it might be because of the type of grape you are using. In this case, after you’ve processed the jam in the blender, return it to the sauce pan, then mix 2 teaspoons of cornstarch with one tablespoon of water, add it to the jam, and bring to a boil. Let jam boil for a couple of minutes until thickened. Remove from the heat and refrigerate until ready to use.
Walnut Buttercream
Process walnuts in a small food processor until crushed. You should obtain about 1 cup of crushed nuts. Make sure the nuts are finely ground, so the buttercream can be smooth.
Sift powdered sugar.
In the bowl of an electric mixer, mix cream cheese and butter. Cream both at medium high speed for 1-2 minutes, scraping the bowl in between.
With the mixer off, add powdered sugar in the bowl. Mix on low and once incorporated, raise the temperature to medium-high and cream for about 30 seconds. Add crushed walnuts and vanilla extract and cream for another 30 seconds until incorporated. Scrape bowl and cream for a few more seconds.
Place frosting in a piping bag lined with the tip of your preference.
To assemble
Using a spoon, remove the center of each cupcake. Fill it with the cool down jam. Place the piece of cake you removed back on top of the cupcake, to protect the filling and give a better base to the frosting that we will pipe on top of the cupcakes.
Frost cupcakes with the walnut buttercream. Decorate with grapes, and figs on top.
Storage
Leftover jam will keep in the fridge for up to 7 days, in case you have any. Cupcakes will hold up well in the fridge, covered, for up to 4 days.