Choose either 2 cups full-fat Greek yogurt, 1 cup full-fat Greek yogurt plus 1 cup cottage cheese, or 2 cups cottage cheese. If using any cottage cheese, blend it for 45 to 60 seconds, scraping down the blender as needed, until completely smooth with no visible curds.

Gently melt 4 ounces dark or semisweet chocolate for the Greek-yogurt or blended-base version. For the full 2-cup cottage-cheese version, melt 6 ounces chocolate instead. Let the chocolate cool for a few minutes so it is warm, not hot.

In a large bowl, whisk the chosen 2-cup base with 1 can (14 ounces) sweetened condensed milk, 1/2 cup unsweetened cocoa powder, the 4 or 6 ounces melted chocolate, 1 teaspoon vanilla extract, and 1/4 teaspoon salt. If using it, whisk in 1 to 2 scoops (30 grams) chocolate protein powder until thick, smooth, and glossy.

Add 1 1/2 to 2 cups fudgy brownie chunks and gently fold just until the pieces are evenly distributed.

Transfer the mixture to a 9-by-5-inch loaf pan, smooth the top, and cover tightly. Freeze for 6 to 8 hours or overnight.

Let the ice cream stand at room temperature for 5 to 10 minutes before scooping.