Preheat the oven to 350 degrees F. Grease an 8-inch cake pan with 1 teaspoon olive oil.
For the fennel: In a medium saucepan over medium heat, dissolve the sugar in 3/4 cup water, stirring occasionally with a wooden spoon. Add the fennel, salt and lemon juice, and bring to a simmer. Reduce the heat to low and cook until the liquid is reduced by three-quarters, about 15 minutes. Spread the candied fennel evenly over the bottom of the prepared cake pan. Set aside to cool slightly.
For the cake: Meanwhile, in a medium bowl, whisk together the flour, sugar, baking powder, baking soda and salt. In a separate bowl, whisk together the milk, eggs, olive oil, lemon zest and fennel pollen. Add the dry ingredients to the wet and whisk until just combined. Pour the batter evenly over the candied fennel. Place in the preheated oven and bake until a toothpick inserted in the middle of the cake comes out clean, 30 minutes. Cool for 10 minutes in the pan, then invert the cake onto a plate to cool completely.
For the sauce: In a small bowl, whisk together the raspberry jam, lemon juice and 2 tablespoons warm water.
Sprinkle the cake with a few picked fennel fronds. Slice into wedges and serve with a spoonful of the sauce.