For filling, in a small heavy saucepan, mix sugar, cornstarch and salt. Whisk in milk. Cook and stir over medium heat until thickened and bubbly. Reduce heat to low; cook and stir 2 minutes longer. Remove from heat. In a small bowl, whisk egg yolks. Whisk a small amount of hot mixture into egg yolks; return all to pan, whisking constantly. Bring to a gentle boil; cook and stir 2 minutes.Remove from heat. Stir in butter until melted. Immediately transfer to a clean bowl; stir in vanilla. Cool 30 minutes. Press plastic wrap onto surface of filling; refrigerate until cold.
Whisk custard gently. Fold in half the whipped cream. Fold in remaining whipped cream. Cover and refrigerate.
While custard is chilling, make dough. In a large bowl, mix sugar, yeast, salt and 1 cup flour. In a small saucepan, heat milk and butter to 120°-130°. Add to dry ingredients; beat on medium speed 1 minute. Add eggs; beat on high 1 minute. Stir in enough remaining flour to form a soft dough (dough will be sticky).
Turn dough onto a well floured surface; knead until smooth and elastic, 6-8 minutes. Place in a greased bowl, turning once to grease the top. Cover and let rise in a warm place until doubled, about 1 hour.
While dough is rising, make almond topping. In a small saucepan over medium heat, melt butter, honey and sugar. Cook and stir until sugar is dissolved. Remove from heat; stir in almonds. Cool slightly and set aside.
Punch down dough. Turn onto a lightly floured surface; roll into a 9-in. circle. Transfer to greased 9-in. springform baking pan, pressing to evenly fill pan with dough. Spoon almond mixture over dough and gently spread to cover entire surface. Cover pan with a kitchen towel; let rise in a warm place untildoubled, 25-30 minutes. Preheat oven to 350°. Bake until topping is golden brown , 25-30 minutes. Cool on a wire rack 10 minutes. Loosen sides from pan with a knife. Cool 1 hour longer.
Remove cake from base of springform pan. Using a long serrated knife, cut cake horizontally in half; spread filling over cake. Replace top of cake. Serve immediately. Chill leftovers.