Step 1In a bowl, gently stir together the orange and grapefruit segments with the orange and lime zest, along with the sugar. If desired, add a little orange juice to thin for more liquid.
Step 1Heat the oven to 350 degrees. Place the almonds in a food processor and pulse to a medium or fine grind.
Step 2Prepare the muffin tins: Spray each muffin tin with vegetable spray and dust with a coating of sugar. Sprinkle about 2 teaspoons of ground almonds on the bottom of each tin. Set aside.
Step 3In a medium bowl, whisk together the remaining ground almonds along with the flour, baking powder and salt.
Step 4In the bowl of a stand mixer fitted with the whisk attachment, or in a large bowl using a hand mixer, beat together the orange and lemon zest along with the sugar and eggs until light, fluffy and doubled in volume, 3 to 5 minutes. Slowly beat in the milk and olive oil until incorporated.
Step 5Gently fold in the flour mixture just until combined. Divide the mixture evenly among the muffin tins, filling each 2/3 to ¾ full.
Step 6Bake in the center of the oven until the top is set and the crown is very lightly browned, 15 to 20 minutes. Remove and cool the racks on a tray.
Step 7While the cakes are still warm, pop them out of the trays and serve, garnished with the citrus relish and whipped cream.