1 1⁄2 cups unbleached all-purpose flour
1⁄3 cup milk
1 teaspoon cinnamon
1 ripe Anjou pear, peeled, cored, and cut into 1⁄3-inch pieces
1 teaspoon baking powder
1⁄2 cup raisins
1⁄4 teaspoon salt
1⁄2 cup toasted walnuts, chopped
13 tablespoons unsalted butter, softened
2 cups sugar
1⁄2 cup water
1⁄2 cup plus 2 tablespoons heavy cream
3 large eggs, room temperature
1 teaspoon fleur de sel or other good-quality sea salt
1 tablespoon pear brandy or unflavored brandy
Preheat the oven to 350ºF. Grease a 9-inch round cake pan and dust it with flour. Combine the flour, cinnamon, baking powder, and salt in a medium mixing bowl.
Combine 8 tablespoons of the butter and 1 1/4 cups of the sugar in a large mixing bowl and cream with an electric mixer on medium-high speed until fluffy, about 3 minutes.
With the mixer on low speed, beat the eggs in, one at a time, scraping down the sides of the bowl after each addition. Stir in the brandy. Stir in 1⁄3 of the flour mixture until just incorporated.
Stir in half the milk. Repeat, ending with the flour mixture and stirring on low until just combined. Stir in the pear, raisins, and nuts.
Scrape the batter into the prepared pan and smooth the top with a rubber spatula. Bake until a toothpick inserted in the centre comes out clean, 45 to 50 minutes.
Let the cake cool in the pan for about 5 minutes, invert it onto a wire rack, and then turn it right side up on a rack to cool completely.
To make the sauce, combine the remaining sugar and water in a small, heavy saucepan. Boil the mixture until it turns a light amber colour; do not stir. If part of the syrup is darkening, gently tilt the pan to even out cooking.
When the syrup is a uniform amber colour, stir in the heavy cream with a long-handled wooden spoon. When the bubbling has subsided, remove the pot from the heat and stir in the remaining butter and salt until the butter is melted.
Transfer the sauce to a large heatproof measuring cup and let cool to warm before using.
Cut the cake into wedges, and serve with sauce on the side. Store leftover cake in a cake keeper, or wrap in plastic and store at room temperature for up to 3 days.