In a small saucepan over medium-low heat, bring dates and coffee or liquid of your choice to a simmer; cook until almost all liquid is absorbed. Remove from heat and let cool. Puree in a food processor until smooth. You should have about 1 cup. 2/3 will be used in cake and 1/3 in the frosting.

Preheat oven to 325. Butter a 9" springform pan. Line with parchment and butter the parchment. Dust with cocoa, tapping out excess. Melt butter and chocolate in microwave at intervals on low setting and whisk until smooth. Remove from heat and whisk in 2/3 c date puree. Let cool and whisk in egg yolks, salt and cinnamon or cardamom.

Beat egg whites on medium-high speed until soft peaks form. Slowly add 1/4 c sugar, beating until stiff, glossy peaks form. Fold 1/3 of the whites into chocolate, then fold in the rest. Transfer to prepared pan, smoothing with an offset spatula.

Bake until set, about  30 minutes. It will crack a bit on the edges and be shiny in center. Cool on a wire rack. After cake has cooled run a paring knife around sides of pan and remove sides. Transfer to a cake plate.

To Make Glaze:

Bring 1 c of sugar and 1/4 c water to a boil, stirring until  sugar has dissolved, about 2 minutes. Let boil without stirring until deep golden brown, swirling pan to color evenly and washing down sides of saucepan with a wet pastry brush occasionally to keep sugar crystals from forming, 10-11 minutes. Remove from heat and carefully pour in cream, it will sputter, and stir to combine. Stir in remaining 1/3 c date puree. Pass through a mesh seive, and let cool until thick but pourable, about 30 minutes.

Pour caramel over cake and spread with an offset spatula so it drips over sides. Sprinkle with flaky sea salt. Slice with a sharp knife dipped in hot water and wipe between each slice. Serve with whipped cream or ice cream.