Thaw and drain 2 cups of frozen rhubarb. Once the rhubarb has thawed cut into small chunks.
In a large mixing bowl combine ½ cup (1 stick) of softened butter and 1 cup of sugar. Using a hand mixer or the whisk attachment of a mixer mix for 1 minute on medium speed or until light and creamy.
Add 2 large eggs and ½ cup of Greek yogurt or sour cream to the bowl. Mix for another 30 seconds or so on medium (the mixture will look a little curdled).
In another mixing bowl combine 2 cups of flour, 1 tsp. baking powder, ½ tsp. baking soda, and a pinch of salt. Mix together with fork.
Add the flour mixture to the wet ingredients a little at a time. Stir ingredients until combined each time. Repeat until all the wet and dry ingredients are totally combined being careful not to over-mix.
Add the chopped rhubarb to the batter and fold it in just until combined.
For The Streusel:
Melt 2 Tbsp. of butter and place in a bowl. Add 4 Tbsp. of brown sugar, 3 Tbsp. of flour, 1 tsp. cinnamon, and a pinch of salt.
Zest 1 lemon and add the zest to the bowl. Stir with a fork until the mixture resembles coarse crumbs or sand.
Pour half of the batter into the bread pan and smooth until even. Pour the streusel over the bottom half of the batter and press down lightly. Pour the remaining half of the batter over the streusel and smooth until even.
Place the pan on the bottom rack of the oven. Bake for 65-70 minutes. Rotate the pan once during the baking process to ensure that it cooks evenly.
Remove the pan from the oven and allow the bread to cool completely.
RECIPE TIP: Fresh or frozen rhubarb can be used in this recipe. Simply substitute the same amount of rhubarb if using fresh.