Preheat oven to 350°F (170°C). Grease the bundt cake pan well with butter and sprinkle with sliced almonds, lining the inside of the pan. Chill the pan, preferably in the freezer.

In a large mixing bowl, beat the butter, sugar, lemon zest and vanilla until fluffy. Beat in the eggs. Beat in the crème fraîche and topfen. Combine the flour with the baking powder and salt and stir the flour mixture into the topfen mixture. The batter will be very thick. Fold in the strawberries. Spoon the batter into the prepared baking pan.

Bake cake for 40-45 minutes, until a wooden toothpick comes out clean or with only a few moist crumbs attached. Remove from oven and allow to cool in the pan for 10 minutes. Turn cake out onto a cooling rack and allow to cool completely. Dust cake with powdered sugar before serving, if desired.

Keep cake covered at room temperature for up to two days, in the refrigerator for up to four days.