R Markdown beamer with subheading aligned below main heading

Question

Below I show a simple example of Markdown Beamer slides. I want to insert a subheading under my main heading. However, I want it to be aligned directly under my main heading, and I want the space between the two headings to be reduced.

MWE:

---
classoption: [t]
output:
  beamer_presentation:
    slide_level: 2
---

---

## Header

### Second Header

- Content

Desired Result:

Answer 1

The problem is that rmarkdown does not set the second header as framesubtitle, but for some reason inserts a block instead. As your beamer theme does not set the colour of blocks, you don't even get to see it ....

Instead you can use the \framesubtitle{...} macro:

---
classoption: [t]
output:
  beamer_presentation:
    slide_level: 2
    keep_tex: true
---

---

## Header

\framesubtitle{Second Header}

- Content