Browned Butter Banana Streusel Cake

Preheat oven to 350F. Position an oven rack in the middle of the oven. Lightly butter or spray a 9×13 baking dish.

In a small stainless steel saucepan or skillet, start melting the butter over medium heat. (The stainless steel pan makes it easy to gauge how brown the butter is, preventing you from scorching or burning it.)

Meanwhile, in a medium bowl, combine the flour, flax meal, baking powder, baking soda, and salt. Whisk to combine.

In a large bowl, measure out the brown sugar. Break up any lumps.

In another medium bowl, mash the bananas. Sprinkle with the cinnamon, nutmeg, and vanilla. Mix well. Add the lemon zest and mix well.

When the butter starts smelling like toffee, watch it closely. Swirl it around to help it cook evenly. When the butter has browned and the milk solids have turned dark brown but not black, take it off heat and pour into the bowl with the brown sugar. Mix with a whisk (the sugar will still look grainy) to combine and to cool. When the butter has cooled down a bit, add the eggs one at a time, whisking well after each addition. Add the sour cream or yogurt and combine well.

Pour the banana mixture into the bowl with the butter, again whisking to combine well. Then add the dry ingredients and gently stir with a spatula until just combined. Fold in the walnuts.

Pour the batter into the prepared pan and bake for 25 minutes.

While the batter is baking, prepare the streusel. Mix the flour, cinnamon, sugar, and salt in a bowl. Using a box grater, grate in the cold butter. Mix the butter and the flour until you have pea-sized crumbs. Stir in the nuts. Keep in the refrigerator until ready to use, so the butter doesn’t melt.

After the cake has baked for 25 minutes, take the dish out and sprinkle the streusel evenly over the top. Return to the oven and continue baking for another 30 to 35 minutes.

Meanwhile, prepare a simple caramel sauce by heating the sugar in a heavy-bottomed saucepan over medium heat. Stir continuously to keep it from burning. When it turns into a dark amber syrup, add the butter and stir vigorously to melt the butter and incorporate it into the sugar. Take the pan off heat and carefully stir in the heavy cream. When the sauce has come together, stir in the vanilla. (Tip: if you want to make a salted caramel sauce, add a teaspoon of kosher salt now.)

Cake is done when an inserted knife comes out with clean with just a few moist crumbs. Cool in the pan on a rack for 15 minutes before slicing.

Serve the cake with a drizzle of caramel sauce. If you’re feeling even more rebellious, top with whipped cream or a scoop of ice cream.