Wow.. just looking at the pictures I can see how dense and moist the cake must be

The cake's denseness was not a bad thing at all — on the contrary, it created the perfect texture for soaking up absorbing a cake soak. I ended up whipping a Grand Marnier cake soak that I poured over the cake before topping it off with powdered sugar and orange zest. The orange flavor complemented the cake's eggy flavor, resulting in one of the most delicious cakes I've had in a long time. I also suggest whipping up a dark chocolate ganache or orange glaze to top the cake off. Or at least, that's what I'll be doing the next time I make this cake. ;-)

Ingredients:
For the Sweetened Condensed Milk Cake:
(makes one 10-inch, 12-cup capacity bundt pan)
1 stick (4 oz.) unsalted butter (plus more for pan)
1 teaspoon orange zest (plus more for garnishing)
8 eggs, at room temperature
2 14-oz. cans sweetened condensed milk
2 cups all-purpose flour (plus more for pan)
1 teaspoon baking powder
1/4 teaspoon salt

For the Grand Marnier Cake Soak:
(enough for one 10-inch cake)
1/2 cup water
1 tablespoon pure vanilla extract
1/4 cup granulated sugar
2 tablespoons unsalted butter
a pinch of salt
1/2 cup Grand Marnier (or any other orange-flavored alcohol)

Recipe:

For the Sweetened Condensed Milk Cake:Preheat the oven to 350 (F). Prepare your bundt pan by either generously spraying with cooking spray or brushing with 1 tablespoon melted butter. Dust generously with flour and flip and tap to remove excess flour.

In a small pot, melt 1 stick unsalted butter with 1 teaspoon orange zest over medium heat, continually stirring with a heatproof rubber spatula to prevent the butter from burning and help infuse it with orange flavor. Set aside to cool.
In the bowl of a freestanding electric mixer with a whisk attachment, whisk together 8 eggs until well beaten. Pour in 2 cans of sweetened condensed milk and whisk until well combined. The mixture should be pale yellow and smooth. Add butter and orange zest mixture (from the second step), and continue whisking until well combined. Once the butter has been incorporated into the milk and eggs, turn the mixer off and replace your whisk attachment with a paddle attachment.

In a small bowl, whisk together 2 cups flour, 1 teaspoon baking powder, and 1/4 teaspoon salt. Sprinkle over the liquid mixture (from the third step), and turn on your mixer to the lowest speed, mixing the ingredients together until just incorporated.
Once the dry ingredients have been incorporated into the liquid ingredients, pour into the greased bundt pan and bake for about 60 minutes — a skewer inserted into the center of the cake should come out completely dry. When the cake is finished, let the cake cool in its pan on a cooling rack completely. While the cake is in the oven, make the Grand Marnier cake soak.

For the Grand Marnier Cake Soak:Combine 1/2 cup water, 1 tablespoon vanilla, 1/4 cup sugar, 2 tablespoons unsalted butter and a pinch of salt in a small pot. Cook over low heat (do not boil!), whisking frequently until the sugar is dissolved and the vanilla is fragrant about 10 minutes.
Once the sugar has dissolved, remove the pot from heat and let the mixture cool to room temperature. Once the mixture has cooled, whisk in 1/2 cup Grand Marnier.

Putting It All Together:Once the cake has cooled in its pan completely, use a wooden skewer to poke holes all over the exposed part of the cake (this will be the bottom of the cake once inserted into a plate).
Pour the Grand Marnier cake soak over the cooled cake and let sit for at least an hour, before inverting onto a plate and garnishing with powdered sugar and orange zest.

source here