Prepare the pan. Preheat an oven to 350°F (180°C) with a rack set in the middle. Line a 9-inch round cake pan with parchment paper, then coat the sides with baking spray.
If you haven’t already, peel and dice the pears. Set aside.
Melt butter. Place ½ cup (113g) butter in a saucepan set over medium heat. Warm until melted, then set aside.
Mix the dry ingredients. In a medium mixing bowl, whisk together 1 cup (120g) all-purpose flour, 1 tsp baking powder, ¼ tsp cinnamon, and ¼ tsp kosher salt.
Mix the wet ingredients. In a larger mixing bowl, whisk together 2 eggs, ½ cup (105g) brown sugar and ¼ cup white sugar until the mixture is pale yellow and ribbons form, about 2-3 minutes. I like to use a hand mixer for this, but you can whisk by hand if preferred. Add half of the melted butter, 3 Tbsp whole milk, 1 tsp almond extract, and 1 tsp vanilla extract or paste, then mix until well combined.
Add dry ingredients. Pour half of the flour mixture in all at once, whisk well, then repeat with the remaining melted butter and flour. There should be no lumps.
Fold in the pears. Add the diced pears, then use a spatula to gently fold into the cake batter. Transfer to the prepared baking dish, then smooth out the top. Sprinkle with the remaining 2 Tbsp (25g) granulated sugar and ¼ cup (20g) sliced almonds, if using.
Bake the cake. Transfer to the preheated oven, then bake for 42-45 minutes, or until a toothpick inserted into the center of the cake comes out clean.
Cool slightly, then serve! Allow the cake to cool in the pan for 10 minutes before carefully inverting onto a cake platter or tray. I like to serve it warm with a scoop of cool, crème fraîche. It’s just as delicious with whipped cream or ice cream!