Preheat oven to 350°. Line 3 (8-inch) cake pans with parchment and spray with baking spray. Set aside. 

Cream butter and sugar until light and fluffy, about 5 minutes. 

Meanwhile, in a bowl, whisk flour (take out 2 tablespoons and put in a small bowl to toss with mini chocolate chips), salt, and baking powder. 

Add the eggs, one at a time, scraping the bowl as needed. Add the vanilla. 

Add one-third of the flour, alternating with the milk, and ending with the flour. Beat each addition until just incorporated, being careful to not overmix. 

Toss the mini chips in the reserved flour and fold into the batter by hand, scraping the bottom and sides of the bowl one last time. 

Divide the batter evenly among the three pans. Bake until a toothpick comes out clean, about 20 minutes. Let cool in pans for 15 minutes, then turn out and cool completely on a wire rack. 

To make the simple syrup, bring sugar and water to a boil in a small saucepan over high heat. Turn off heat and let cool completely.

To make the buttercream, beat the butter in the bowl of a stand mixer until pale yellow, about 5 minutes. Add half of the sugar and beat until well incorporated, then add the remaining sugar, vanilla, and salt. Add the heavy cream and beat on medium speed until very light and fluffy, about another 3 to 4 minutes. Fold in chocolate chips. 

To assemble the cake, brush each layer generously with simple syrup. 

Dab about a tablespoon of buttercream on the platter or cake board that you are going to be decorating your cake on. Add the first layer of cake and center on the board. Spread an even layer of buttercream over the layer and add the second cake layer. Repeat with the third layer. Ice the sides and top of the cake with remaining buttercream. Add more chips and flowers for decorations if desired.