Preheat the oven to 350°. Butter and flour a 9-by-4 1/2-by-3-inch metal loaf pan. In the bowl of a standing electric mixer fitted with the paddle, beat the butter with 1 3/4 cups of flour and the salt, vanilla seeds and orange zest until creamy. Scrape the mixture into a bowl. Add the egg yolks, whole eggs and sugar to the mixer bowl and beat at medium-high speed with the whisk attachment until pale and thick, about 4 minutes. Stir half of the whipped eggs into the flour paste, then fold in the rest.
Scrape the batter into the loaf pan and bake in the center of the oven for 1 1/2 hours, until the cake is risen and a skewer inserted in the center comes out clean. Let the pound cake cool in the pan for 30 minutes, then turn out onto a wire rack to cool completely.
In a 9-by-13-inch nonreactive baking dish, combine the fennel, vanilla bean, a pinch of salt and 2 tablespoons of water. Cover with foil and roast until the fennel is tender, 30 minutes. Meanwhile, in a medium bowl, toss the strawberries with the sugar, lemon juice, vanilla seeds and a pinch of salt and let stand until juicy, 30 minutes.
Add the strawberries and their juices to the fennel, cover and roast for 30 minutes. Discard the vanilla bean and transfer the compote to a bowl. Slice the cake and set a slice on each plate. Top with the compote, sprinkle with fennel pollen and serve.