Bring a large saucepan with 1 inch of water to a simmer over medium-high heat. Stir the strawberries, lemon zest and 1/4 cup of the sugar in a large stainless steel mixing bowl, cover with plastic wrap and place on top of the simmering pot (the bottom of the bowl shouldn’t touch the water). Reduce the heat to medium-low, and let the strawberries macerate over the simmering water for 20 minutes. Remove the bowl from the pot and refrigerate until chilled. (Note: The strawberry sauce can be made up to 1 day in advance.).
Preheat the oven to 350 degrees. Place a 10-inch cake pan on parchment paper; trace and cut out a circle. Spray the pan with nonstick spray, then place the round piece of parchment into the bottom of the pan and spray one more time. Sprinkle a couple of spoonfuls of flour into the pan, tap and coat bottom and sides of the pan and discard any excess flour.
Cut the 1 1/2 sticks of butter into small pieces and melt in a medium saucepan over medium-high heat. Simmer, whisking often to incorporate any solids that sink to the bottom, until the butter is a golden-amber color and smells nutty, 4 to 6 minutes. Set the butter aside to cool.
To prepare the cake: In a large bowl, whisk eggs and 1 cup sugar vigorously for about 2 minutes. The mixture will be bright yellow. Set whisk aside and continue by using an electric mixer to whip the eggs and remaining 1/4 cup sugar on high speed until the mixture is thick and pale in color (4 to 5 minutes more). Reduce speed to low and slowly (adding too quickly will cause mixture to separate) add in the cooled brown butter making sure to scrape in all of the brown bits.
Sift flour, baking powder and salt together. Using a whisk, gently fold in one-third of dry ingredients into the batter, then half the buttermilk. Repeat, ending with the last third of the dry mixture. Scrape the batter into the prepared pan. Bake until the cake sides pull away from the pan and a toothpick inserted into the center comes out clean, about 25 minutes. If the cake appears to be browning too quickly, cover lightly with foil in the last 10 minutes of baking. Let cake cool on a wire rack for about 20 minutes before removing from pan. Run a knife around the edge of the pan and invert it onto a wire rack to cool completely.
For the Chantilly Cream: Pour the heavy cream into the bowl of a stand mixer, add the vanilla and sift in the confectioners' sugar. Whip on low speed to combine and then increase the speed to medium-high. Whip until medium-stiff peaks form, about 1 1/2 minutes.
Transfer the cake to a plate and slice into wedges. Serve topped with strawberries, sauce and a dollop of Chantilly Cream or slice each wedge in half horizontally and sandwich the halves with strawberries and sauce, then top with cream.