Prepare the cake (the cake is best prepared the day before. Wrap and store overnight).
Place rack in the center of the oven, preheat to 350º F. Lightly oil a 9 x 5 inch loaf pan, dust with flour, shaking out any excess. Set pan aside.
In a large bowl, whisk together the eggs, sugar and salt; mix until foamy and smoothly blended. Whisk in the grated zest.
Spoon the flour and baking powder into a sifter (if you don't have a sifter, use a fine mesh colander or strainer); sift about a third into the eggs' whisk lightly until combined, do not beat. Continue two more times; sifting flour into the batter and whisking until just incorporated. Whisk in the heavy cream; then the oil.
Pour the batter into the prepared pan; bake 50 - 60 minutes, or until a toothpick inserted into the center comes out clean. Remove to a cooling rack; allow to cool 10 minutes before unmolding. Cool to room temperature, right side up, on the rack. When cool, wrap with plastic wrap if allowing to sit overnight. Makes 10 - 12 servings.
Wash and cut the fruits in half. Remove the pits.
Combine the honey, vinegar and vanilla in a small bowl. Mix Well.
Prepare the grill to medium. Be sure to clean it well of any cooked matter as you don't want your dessert tasting of dinner
Slice the cake into slices. Place on grill and grill, turning once or twice, until lightly toasted.
Place the fruit on the grill, cut side down. Grill for a few minutes, turn, brush with glaze; grill, turning and basting the cut side with the glaze until the fruit is tender, but firm, and the cut side is golden and caramelized (take care it does not burn, honey likes to burn). Once cooked, remove to a cutting board and slice the fruit.
Arrange the fruits on slices of toasted cake. top with whipped cream. Sprinkle with a bit of coarse salt, if desired.