Dough

In a bowl of kitchen aid stand mixer, whisk flour, yeast, and salt together. Whisk milk, melted butter, sugar, and egg in a 2 cup measuring bowl until sugar has dissolved. Using a dough hook on low speed, slowly add milk mixture to flour mixture and mix until cohesive dough starts to form and now dry flour remains, about 2 minutes, scraping down the sides as needed. Increase speed to medium-low and knead until dough is smooth and elastic and clears sides of bowl but still sticks to bottom, 8 to 12 minutes.

Transfer dough to a well-floured counter. Using your well-floured hands, knead dough to form a smooth, round ball, about 30 seconds. Place dough seam side down in a lightly greased large bowl, and cover tightly with plastic wrap. Let rise until doubled in size, 1 to 1 ½ hours. (Unrisen dough can be refrigerated for at least 8 hours or up to 16 hours; let dough sit at room temperature for 1 hour before shaping.)

Make the filling

In a bowl of stand mixer fitted with paddle, beat cream cheese, sugar, flour, and lemon zest on low speed until smooth, about 1 minute. Add ricotta and beat until just combined, about 30 seconds. Transfer to bowl, cover with plastic, and refrigerate until ready to use.

Make the streusel

In a bowl combine flour, sugar, and butter in bowl and rub between fingers until mixture resembles wet sand. Cover with plastic and refrigerate until ready to use.

Make the strawberry fillings

In a skillet add strawberries and sugar and cook in medium low flame until strawberries break down and starts release juice mash with help of masher into coarse puree and set aside.

Line baking sheets with parchment paper. Punch down dough and place on lightly floured counter. Divide the dough into 9 equal pieces 67g or (about 2 ¼ ounce each) and cover loosely with greased plastic. Working one piece of dough at a time (keep remaining pieces covered), form into rough ball by stretching dough around your thumbs and pinching edges together so that the top is smooth. Place the ball seam side down on a clean counter and, using your cupped hand, drag in small circles until dough feels taut and round.

Arrange dough balls seam side down on prepared sheets, spaced about 1 ½ inches apart. Cover loosely with greased plastic and let rise until increased in size by about half, 1 ½ to 2 hours.

Adjust oven racks to upper-middle positions and heat oven to 350 degrees. Grease and flour bottom of a round ⅓-cup dry measuring cup. Press the cup firmly into the center of each dough round until the cup touches the sheet to make indentation for filling. (Reflour the cup as needed to prevent sticking.)

Divide filling evenly among kolaches (about 1 ½ tablespoons each) and smooth with the back of a spoon. Gently brush the edges with egg mixture and sprinkle with streusel. (Make sure not to sprinkle streusel over filling.) Bake until golden brown, about 12minutes, switching and rotating sheets halfway though baking. Transfer kolaches to wire rack and let cool for 20 minutes. Serve warm.